JPH0969590A - Silicon nitride circuit substrate - Google Patents
Silicon nitride circuit substrateInfo
- Publication number
- JPH0969590A JPH0969590A JP34423595A JP34423595A JPH0969590A JP H0969590 A JPH0969590 A JP H0969590A JP 34423595 A JP34423595 A JP 34423595A JP 34423595 A JP34423595 A JP 34423595A JP H0969590 A JPH0969590 A JP H0969590A
- Authority
- JP
- Japan
- Prior art keywords
- silicon nitride
- circuit board
- substrate
- thermal conductivity
- layer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- Cooling Or The Like Of Semiconductors Or Solid State Devices (AREA)
Abstract
Description
【0001】[0001]
【発明の属する技術分野】本発明は半導体素子を搭載し
た窒化けい素回路基板に係り、特に放熱特性,機械的強
度および耐熱サイクル特性を改善できるとともに実装性
に優れた窒化けい素回路基板に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a silicon nitride circuit board on which a semiconductor element is mounted, and more particularly to a silicon nitride circuit board which can improve heat dissipation characteristics, mechanical strength and heat resistance cycle characteristics and is excellent in mountability.
【0002】[0002]
【従来の技術】従来からアルミナ(Al2 O3 )焼結体
などのように絶縁性に優れたセラミックス基板の表面
に、導電性を有する金属回路層をろう材で一体に接合
し、さらに金属回路層の所定位置に半導体素子を搭載し
た回路基板が広く普及している。2. Description of the Related Art Conventionally, a conductive metal circuit layer is integrally joined with a brazing material to the surface of a ceramic substrate having excellent insulating properties such as an alumina (Al 2 O 3 ) sintered body, A circuit board in which a semiconductor element is mounted at a predetermined position on a circuit layer is widely used.
【0003】一方、窒化けい素を主成分とするセラミッ
クス焼結体は、一般に1000℃以上の高温度環境下で
も優れた耐熱性を有し、かつ耐熱衝撃性にも優れている
ことから、従来の耐熱性超合金に代わる高温構造材料と
してガスタービン用部品、エンジン用部品、製鋼用機械
部品等の各種高強度耐熱部品への応用が試みられてい
る。On the other hand, a ceramic sintered body containing silicon nitride as a main component generally has excellent heat resistance even in a high temperature environment of 1000 ° C. or higher, and also has excellent thermal shock resistance. As a high-temperature structural material that replaces the heat-resistant superalloy described above, it has been tried to be applied to various high-strength heat-resistant parts such as gas turbine parts, engine parts, and steel-making machine parts.
【0004】従来より窒化けい素セラミックス焼結体の
組成として、窒化けい素に酸化イットリウム(Y
2 O3 ),酸化セリウム(CeO),酸化カルシウム
(CaO)などの希土類元素あるいはアルカリ土類元素
の酸化物を焼結助剤として添加されたものが知られてお
り、これら焼結助剤により焼結性を高めて緻密化・高強
度化が図られている。Conventionally, as a composition of a silicon nitride ceramics sintered body, yttrium oxide (Y
2 O 3 ), cerium oxide (CeO), calcium oxide (CaO) and other rare earth elements or alkaline earth element oxides are known to be added as sintering aids. The sinterability is enhanced to achieve higher density and higher strength.
【0005】従来の窒化けい素焼結体は、窒化けい素原
料粉末に上記のような焼結助剤を添加し成形し、得られ
た成形体を1600〜2000℃程度の温度で焼成炉で
所定時間焼成した後に炉冷し、得られた焼結体を研削研
摩加工する製法で製造されている。A conventional silicon nitride sintered body is formed by adding the above-mentioned sintering aid to a silicon nitride raw material powder, and molding the obtained molded body at a temperature of about 1600 to 2000 ° C. in a firing furnace. It is manufactured by a manufacturing method in which after firing for a time, the furnace is cooled, and the resulting sintered body is ground and polished.
【0006】[0006]
【発明が解決しようとする課題】しかしながら、上記従
来方法によって製造された窒化けい素焼結体では、靭性
値などの機械的強度は優れているものの、熱伝導特性の
点では、他の窒化アルミニウム(AlN)焼結体、酸化
ベリリウム(BeO)焼結体や炭化けい素(SiC)焼結体
などと比較して著しく低いため、特に放熱性を要求され
る半導体用回路基板などの電子用材料としては実用化さ
れておらず、用途範囲が狭い難点があった。However, although the silicon nitride sintered body manufactured by the above-mentioned conventional method has excellent mechanical strength such as toughness, it is different from other aluminum nitrides in terms of thermal conductivity. AlN) sintered body, beryllium oxide (BeO) sintered body, silicon carbide (SiC) sintered body, etc. are significantly lower than those in electronic materials such as semiconductor circuit boards that require heat dissipation. Has not been put to practical use, and has a drawback that its application range is narrow.
【0007】一方窒化アルミニウム焼結体は他のセラミ
ックス焼結体と比較して高い熱伝導率と低熱膨張係数の
特長を有するため、高速化、高出力化、多機能化、大型
化が進展する半導体素子(チップ)を搭載するための回
路基板部品やパッケージ材料として広く使用されてい
る。しかしながら、AlN焼結体は機械的強度の点で充
分に満足できるものは得られていないため、回路基板の
実装工程において破損を生じたり、実装工程が煩雑にな
って半導体装置の製造効率が低下する問題点があった。On the other hand, the aluminum nitride sintered body has the characteristics of high thermal conductivity and low thermal expansion coefficient as compared with other ceramics sintered bodies, and therefore, higher speed, higher output, multi-functionality and larger size are progressing. It is widely used as a circuit board component for mounting a semiconductor element (chip) and a package material. However, since AlN sintered bodies have not been obtained that are sufficiently satisfactory in terms of mechanical strength, damage may occur during the circuit board mounting process, or the mounting process may become complicated, and the manufacturing efficiency of semiconductor devices may decrease. There was a problem to do.
【0008】すなわち、上記窒化アルミニウム焼結体基
板や酸化アルミニウム焼結体基板などのセラミックス基
板を主たる構成材とする回路基板を、アッセンブリ工程
にて実装ボートにねじ止め等により固定しようとする
と、ねじの押圧力による僅かな変形やハンドリング時の
衝撃によって回路基板が破損し、半導体装置の製造歩留
りを大幅に低減させる場合がある。That is, when a circuit board whose main constituent material is a ceramics substrate such as the above aluminum nitride sintered body substrate or aluminum oxide sintered body substrate is fixed to the mounting boat by screwing or the like in the assembly process, In some cases, the circuit board may be damaged by a slight deformation due to the pressing force of or and the impact at the time of handling, and the manufacturing yield of the semiconductor device may be significantly reduced.
【0009】さらに回路基板の強度が小さいため、大型
の回路基板を形成することが困難であり、小型のセラミ
ックス基板上面に1個の半導体素子を搭載した小型の回
路基板が多く用いられていた。そのため、半導体装置を
組み立てる際には、要求される機能数に応じて多数の回
路基板を個別に装置本体に組み込む方式となるため、実
装工程が煩雑になり、半導体装置の製造効率が低下する
問題点があった。Further, since the strength of the circuit board is small, it is difficult to form a large circuit board, and a small circuit board having one semiconductor element mounted on the upper surface of a small ceramic board has been widely used. Therefore, when assembling the semiconductor device, many circuit boards are individually incorporated into the device body according to the number of functions required, which complicates the mounting process and reduces the manufacturing efficiency of the semiconductor device. There was a point.
【0010】また上記のような窒化アルミニウム基板表
面に金属回路層および半導体素子を一体に接合して形成
した回路基板においては、窒化アルミニウム基板自体の
機械的強度および靭性が不充分であったため、半導体素
子の作動に伴う繰り返しの熱サイクルを受けて、金属回
路層の接合部付近の窒化アルミニウム基板にクラックが
発生し易く、耐熱サイクル特性および信頼性が低いとい
う問題点があった。Further, in the circuit board formed by integrally bonding the metal circuit layer and the semiconductor element on the surface of the aluminum nitride substrate as described above, the mechanical strength and toughness of the aluminum nitride substrate itself are insufficient, so that the semiconductor Due to repeated thermal cycles associated with the operation of the element, cracks are likely to occur in the aluminum nitride substrate in the vicinity of the joint portion of the metal circuit layer, and the heat cycle characteristics and reliability are low.
【0011】本発明は上記のような課題要請に対処する
ためになされたものであり、窒化けい素焼結体が本来備
える高強度高靭性特性を利用し、さらに熱伝導率が高く
放熱性に優れるとともに耐熱サイクル特性を大幅に改善
できる一方、半導体装置へのアッセンブリ工程における
実装性を改善した窒化けい素回路基板を提供することを
目的とする。The present invention has been made in order to meet the above-mentioned demands, and utilizes the high-strength and high-toughness characteristics originally possessed by a silicon nitride sintered body, and further has high thermal conductivity and excellent heat dissipation. At the same time, it is an object of the present invention to provide a silicon nitride circuit board which can greatly improve the heat-resistant cycle characteristics while improving the mountability in the process of assembling the semiconductor device.
【0012】[0012]
【課題を解決するための手段】本発明者は上記目的を達
成するために、回路基板の放熱性(熱伝導率)を劣化さ
せず、強度および靭性値を共に満足するような基板材料
を研究するとともに、回路基板のアッセンブリ工程にお
いて発生する締め付け割れや熱サイクル付加時に発生す
るクラックを防止し実装性を改善する対策について鋭意
研究を重ねた。その結果、基板材料については、組成お
よび製造条件を適正に制御することにより、従来にはな
い高い熱伝導率を有する窒化けい素焼結体が得られたこ
と、この窒化けい素焼結体を使用して大型の基板を形成
し、基板表面に回路層を一体に形成するとともに複数の
半導体素子を搭載して大型の回路基板とした場合におい
ても、アッセンブリ工程における回路基板の締め付け割
れ等を効果的に低減できること、耐熱サイクル特性を大
幅に改善できること、アッセンブリ工程における回路基
板の実装性を大幅に改善できること、などを見出し本発
明を完成するに至った。In order to achieve the above object, the present inventor has researched a substrate material which does not deteriorate the heat dissipation (thermal conductivity) of a circuit board and satisfies both strength and toughness values. At the same time, we conducted extensive research on measures to prevent tightening cracks that occur in the assembly process of circuit boards and cracks that occur when heat cycles are applied and improve mountability. As a result, regarding the substrate material, by appropriately controlling the composition and manufacturing conditions, a silicon nitride sintered body having an unprecedented high thermal conductivity was obtained, and this silicon nitride sintered body was used. To form a large-sized circuit board and to integrally form a circuit layer on the surface of the circuit board and to mount a plurality of semiconductor elements into a large-sized circuit board, effectively prevent the circuit board from tightening cracks in the assembly process. The inventors have completed the present invention by finding that it can be reduced, the heat resistance cycle characteristics can be greatly improved, and the circuit board mountability in the assembly process can be greatly improved.
【0013】すなわち、本発明者は、従来使用されてい
た窒化けい素粉末の種類、焼結助剤や添加物の種類およ
び添加量、焼結条件に検討を加え、従来の窒化けい素焼
結体の有する熱伝導率の2倍以上の高い熱伝導性を有す
る窒化けい素焼結体を開発した。さらに、この窒化けい
素焼結体を基板材料として使用し、その表面に、導電性
を有する金属回路層を一体に接合し、さらに複数の半導
体素子を同一基板上に搭載して大型の回路基板を製造し
た場合においても、機械的強度、靭性値、耐熱サイクル
特性、放熱性および実装性を全て満足する窒化けい素回
路基板が得られることを実験により確認した。That is, the inventors of the present invention have studied the type of silicon nitride powder, the type and amount of sintering aids and additives, and the sintering conditions that have been conventionally used, and found that the conventional silicon nitride sintered body Has developed a silicon nitride sintered body having a high thermal conductivity which is more than twice as high as that of. Further, using this silicon nitride sintered body as a substrate material, a metal circuit layer having conductivity is integrally bonded to the surface thereof, and a plurality of semiconductor elements are mounted on the same substrate to form a large circuit board. It was confirmed by an experiment that even when manufactured, a silicon nitride circuit board satisfying all of mechanical strength, toughness value, heat cycle characteristics, heat dissipation and mountability can be obtained.
【0014】具体的には、微細で高純度を有する窒化け
い素粉末に希土類元素酸化物等を所定量ずつ添加した原
料混合体を成形脱脂し、得られた成形体を所定温度で一
定時間加熱保持して緻密化焼結を実施した後、所定値以
下の冷却速度で徐冷し、得られた焼結体を研削研摩加工
して製造したときに熱伝導率が従来の窒化けい素焼結体
の2倍以上、具体的には60W/m・K以上と大きく向
上し、かつ高強度高靭性を有する窒化けい素焼結体が得
られることが判明し、放熱特性および強度特性を共に満
足する新規な窒化けい素材料を開発した。そして、この
窒化けい素材料を、回路基板の基板材料に適用したとき
に、優れた放熱特性と耐久性と耐熱サイクル特性と実装
性とを同時に改善できることが判明した。Specifically, a raw material mixture obtained by adding a predetermined amount of a rare earth element oxide or the like to fine and highly pure silicon nitride powder is molded and degreased, and the obtained molded body is heated at a predetermined temperature for a certain period of time. After carrying out densification sintering while holding, gradually cooling at a cooling rate below a predetermined value, and when the resulting sintered body was ground and polished, the thermal conductivity of the conventional silicon nitride sintered body was increased. It has been found that a silicon nitride sintered body having a high strength and a high toughness, which is significantly improved by more than twice, specifically, 60 W / m · K or more, can be obtained, and a new one satisfying both heat dissipation characteristics and strength characteristics. Developed a new silicon nitride material. It has been found that when this silicon nitride material is applied to a board material of a circuit board, excellent heat dissipation characteristics, durability, heat cycle characteristics, and mountability can be simultaneously improved.
【0015】また、酸素や不純物陽イオン元素含有量を
低減した高純度の窒化けい素原料粉末を使用し、上記条
件にて焼結することにより、粒界相におけるガラス相
(非晶質相)の生成を効果的に抑制でき、粒界相におけ
る結晶化合物相の割合を20%以上(粒界相全体に対
し)、より好ましくは50%以上とすることにより、希
土類元素酸化物のみを原料粉末に添加した場合において
も60W/m・K以上、さらに好ましくは80W/m・
K以上の高熱伝導率を有する窒化けい素焼結体基板が得
られるという知見を得た。A glass phase (amorphous phase) in the grain boundary phase is obtained by using a high-purity silicon nitride raw material powder having a reduced content of oxygen and impurity cation elements and sintering the powder under the above conditions. The formation of the rare earth element oxide alone can be effectively suppressed by controlling the ratio of the crystalline compound phase in the grain boundary phase to 20% or more (to the entire grain boundary phase), and more preferably 50% or more. 60 W / mK or more, more preferably 80 W / mK
It was found that a silicon nitride sintered body substrate having a high thermal conductivity of K or higher can be obtained.
【0016】また、従来、焼結操作終了後に焼成炉の加
熱用電源をOFFとして焼結体を炉冷していた場合に
は、冷却速度が毎時400〜800℃と急速であった
が、本発明者の実験によれば、特に冷却速度を毎時10
0℃以下に緩速に制御することにより、窒化けい素焼結
体組織の粒界相が非結晶質状態から結晶相を含む相に変
化し、高強度特性と高伝熱特性とが同時に達成されるこ
とが判明した。Further, conventionally, when the heating power source of the firing furnace was turned off after the sintering operation and the sintered body was cooled in the furnace, the cooling rate was as rapid as 400 to 800 ° C./hour. According to the experiments by the inventor, the cooling rate is 10
By controlling the temperature slowly to 0 ° C or lower, the grain boundary phase of the silicon nitride sintered body structure changes from an amorphous state to a phase containing a crystalline phase, and high strength characteristics and high heat transfer characteristics are simultaneously achieved. It turned out that
【0017】このような高熱伝導性窒化けい素焼結体自
体は、その一部が既に本発明者により特許出願されてお
り、さらに特開平6−135771号公報および特開平
7−48174号公報によって出願公開されている。そ
して、これらの特許出願において記載されている窒化け
い素焼結体は、希土類元素を酸化物に換算して2.0〜
7.5重量%含有するものである。しかしながら、本発
明者はさらに改良研究を進めた結果、含有される希土類
元素は酸化物に換算して7.5重量%を超えた場合の方
が焼結体の高熱伝導化がさらに進み、焼結性も良いこと
を見い出し、本願発明を完成したものである。特に希土
類元素がランタノイド系列の元素である場合に、その効
果は顕著である。ちなみに粒界相中における結晶化合物
相の粒界相全体に対する割合が60〜70%である場合
においても、焼結体は110〜120W/m・K以上の
高熱伝導率を達成することができる。A part of the high thermal conductivity silicon nitride sintered body itself has already been applied for a patent by the present inventor, and further applied in Japanese Patent Application Laid-Open Nos. 6-135771 and 7-48174. It has been published. The silicon nitride sintered bodies described in these patent applications convert the rare earth elements into oxides of 2.0 to
It contains 7.5% by weight. However, as a result of further improvement research conducted by the present inventor, when the contained rare earth element exceeds 7.5% by weight in terms of oxide, the sintered body has a higher thermal conductivity, and the sintered body has a higher thermal conductivity. The inventors of the present invention have completed the invention by discovering that the connectivity is also good. In particular, the effect is remarkable when the rare earth element is a lanthanoid series element. By the way, even when the ratio of the crystal compound phase in the grain boundary phase to the whole grain boundary phase is 60 to 70%, the sintered body can achieve a high thermal conductivity of 110 to 120 W / m · K or more.
【0018】このように高強度特性および高伝熱特性を
共に満足する窒化けい素焼結体を基板材料とし、金属回
路層を基板材料表面に一体に接合して回路基板を形成す
ることにより、回路基板全体の靭性強度および熱伝導性
を改善することができ、特に回路基板のアッセンブリ工
程における締め付け割れや熱サイクルの付加によるクラ
ックの発生を効果的に防止できることが判明した。特に
上記窒化けい素焼結体を使用して大型基板を作成し、そ
の基板表面に回路層を一体に形成するとともに複数の半
導体素子を搭載して大型の回路基板とした場合において
も、アッセンブリ工程における締め付け割れが発生する
ことが少なく製造歩留りが向上すると同時に、回路基板
の実装工程が単純になり、半導体装置の製造効率を大幅
に改善できることが判明した。As described above, the silicon nitride sintered body satisfying both the high strength property and the high heat transfer property is used as the substrate material, and the metal circuit layer is integrally bonded to the surface of the substrate material to form the circuit board. It has been found that the toughness and thermal conductivity of the entire board can be improved, and in particular, the occurrence of tightening cracks in the circuit board assembly process and cracks due to the addition of heat cycles can be effectively prevented. In particular, even when a large-sized substrate is created using the above silicon nitride sintered body, a circuit layer is integrally formed on the surface of the substrate, and a plurality of semiconductor elements are mounted to form a large-sized circuit board, It has been found that tightening cracks are less likely to occur and the manufacturing yield is improved, and at the same time, the circuit board mounting process is simplified and the semiconductor device manufacturing efficiency can be significantly improved.
【0019】本発明は上記知見に基づいて完成されたも
のである。すなわち本発明に係る窒化けい素回路基板
は、希土類元素を酸化物に換算して2.0〜17.5重
量%、不純物陽イオン元素としてのLi,Na,K,F
e,Ca,Mg,Sr,Ba,Mn,Bを合計で0.3
重量%以下含有し、熱伝導率が60W/m・K以上であ
る高熱伝導性窒化けい素基板に回路層を接合した回路基
板であり、上記高熱伝導性窒化けい素基板上に回路層を
介して複数の半導体素子を搭載したことを特徴とする。The present invention has been completed based on the above findings. That is, in the silicon nitride circuit board according to the present invention, the rare earth element is converted into oxide in an amount of 2.0 to 17.5% by weight, and Li, Na, K and F as impurity cation elements are used.
e, Ca, Mg, Sr, Ba, Mn, B total 0.3
A circuit board in which a circuit layer is bonded to a high thermal conductivity silicon nitride substrate containing less than or equal to wt% and having a thermal conductivity of 60 W / mK or more, and a circuit layer is provided on the high thermal conductivity silicon nitride substrate. And a plurality of semiconductor elements are mounted.
【0020】また本発明に係る窒化けい素回路基板は、
希土類元素を酸化物に換算して2.0〜17.5重量
%、不純物陽イオン元素としてのLi,Na,K,F
e,Ca,Mg,Sr,Ba,Mn,Bを合計で0.3
重量%以下含有し、窒化けい素結晶および粒界相から成
るとともに粒界相中における結晶化合物相の粒界相全体
に対する割合が20%以上であり、熱伝導率が60W/
m・K以上である高熱伝導性窒化けい素基板に回路層を
接合した回路基板であり、上記高熱伝導性窒化けい素基
板上に回路層を介して複数の半導体素子を搭載したこと
を特徴とする。The silicon nitride circuit board according to the present invention comprises:
2.0 to 17.5 wt% of rare earth elements converted to oxides, Li, Na, K, F as impurity cation elements
e, Ca, Mg, Sr, Ba, Mn, B total 0.3
It is contained in an amount of up to 20% by weight, is composed of a silicon nitride crystal and a grain boundary phase, and the ratio of the crystal compound phase in the grain boundary phase to the entire grain boundary phase is 20% or more and the thermal conductivity is 60 W /
A circuit board in which a circuit layer is bonded to a high thermal conductivity silicon nitride substrate of m · K or more, wherein a plurality of semiconductor elements are mounted on the high thermal conductivity silicon nitride substrate via the circuit layer. To do.
【0021】さらに高熱伝導性窒化けい素基板は、希土
類元素を酸化物に換算して2.0〜17.5重量%含有
し、窒化けい素結晶および粒界相から成るとともに粒界
相中における結晶化合物相の粒界相全体に対する割合が
50%以上である窒化けい素焼結体から形成してもよ
い。Further, the high thermal conductivity silicon nitride substrate contains a rare earth element in an amount of 2.0 to 17.5 wt% in terms of oxide, and is composed of a silicon nitride crystal and a grain boundary phase, and in the grain boundary phase. It may be formed from a silicon nitride sintered body in which the ratio of the crystalline compound phase to the entire grain boundary phase is 50% or more.
【0022】また高熱伝導性窒化けい素基板の三点曲げ
強度を650MPa以上にするとよい。さらに高熱伝導
性窒化けい素基板の厚さは回路層の厚さの2倍以下に設
定するとよい。It is preferable that the three-point bending strength of the high thermal conductivity silicon nitride substrate is 650 MPa or more. Further, the thickness of the silicon nitride substrate having high thermal conductivity may be set to be twice the thickness of the circuit layer or less.
【0023】また高熱伝導性窒化けい素基板の熱伝導率
が90W/m・K以上であることがさらに好ましい。ま
た回路層が金属回路板であり、この金属回路板が表面に
酸化層を有する高熱伝導性窒化けい素基板上に接合され
るように構成してもよい。さらに回路層が金属回路板で
あり、Ti,Zr,HfおよびNbから選択される少な
くとも1種の活性金属を含有する活性金属ろう材層を介
して上記金属回路板が高熱伝導性窒化けい素基板上に接
合されるように構成してもよい。また回路層は高融点金
属メタライズ層から構成してもよい。It is further preferable that the high thermal conductivity silicon nitride substrate has a thermal conductivity of 90 W / m · K or more. Alternatively, the circuit layer may be a metal circuit board, and the metal circuit board may be bonded onto a high thermal conductivity silicon nitride substrate having an oxide layer on its surface. Further, the circuit layer is a metal circuit board, and the metal circuit board has a high thermal conductivity silicon nitride substrate through an active metal brazing material layer containing at least one active metal selected from Ti, Zr, Hf and Nb. It may be configured to be bonded on top. The circuit layer may also be composed of a refractory metallized layer.
【0024】さらに希土類元素としてはランタノイド系
列の元素を上記の窒化けい素基板に含有させることが熱
伝導率を向上させるために特に好ましい。Further, it is particularly preferable that a lanthanoid series element is contained as the rare earth element in the above silicon nitride substrate in order to improve the thermal conductivity.
【0025】また、窒化アルミニウムまたはアルミナを
1.0重量%以下添加して窒化けい素基板を構成しても
よい。さらにアルミナを1.0重量%以下と窒化アルミ
ニウムを1.0重量%以下とを併用してもよい。Further, aluminum nitride or alumina may be added in an amount of 1.0% by weight or less to form a silicon nitride substrate. Further, 1.0% by weight or less of alumina and 1.0% by weight or less of aluminum nitride may be used together.
【0026】また本発明において使用する高熱伝導性窒
化けい素焼結体は、Ti,Zr,Hf,V,Nb,T
a,Cr,Mo,Wからなる群より選択される少なくと
も1種を酸化物に換算して0.1〜3.0重量%含有す
ることが好ましい。このTi,Zr,Hf,V,Nb,
Ta,Cr,Mo,Wから成る群より選択される少なく
とも1種は、酸化物、炭化物、窒化物、けい化物、硼化
物として窒化けい素原料粉末に添加することにより含有
させることができる。The high thermal conductivity silicon nitride sintered body used in the present invention is made of Ti, Zr, Hf, V, Nb and T.
It is preferable that at least one selected from the group consisting of a, Cr, Mo, and W is contained in an amount of 0.1 to 3.0 wt% in terms of oxide. This Ti, Zr, Hf, V, Nb,
At least one selected from the group consisting of Ta, Cr, Mo, and W can be contained by adding it to the silicon nitride raw material powder as an oxide, a carbide, a nitride, a silicide, or a boride.
【0027】さらに本発明で使用する高熱伝導性窒化け
い素焼結体の製造方法は、酸素を1.7重量%以下、不
純物陽イオン元素としてのLi,Na,K,Fe,C
a,Mg,Sr,Ba,Mn,Bを合計で0.3重量%
以下、α相型窒化けい素を90重量%以上含有し、平均
粒径1.0μm以下の窒化けい素原料粉末に、希土類元
素を酸化物に換算して2.0〜17.5重量%と、必要
に応じてアルミナおよび窒化アルミニウムの少なくとも
一方を1.0重量%以下添加した原料混合体を成形して
成形体を調製し、得られた成形体を脱脂後、温度180
0〜2100℃で雰囲気加圧焼結し、上記焼結温度か
ら、上記希土類元素により焼結時に形成された液相が凝
固する温度までに至る焼結体の冷却速度を毎時100℃
以下にして徐冷することを特徴とする。得られた焼結体
を所定形状に研削研磨加工して本発明で使用する高熱伝
導性窒化けい素基板が製造される。Further, in the method for producing a high thermal conductivity silicon nitride sintered body used in the present invention, oxygen is 1.7 wt% or less, and Li, Na, K, Fe and C as impurity cation elements are used.
0.3% by weight of a, Mg, Sr, Ba, Mn, B in total
Hereinafter, the content of the α-phase type silicon nitride is 90% by weight or more, and the raw material powder of silicon nitride having an average particle size of 1.0 μm or less is 2.0 to 17.5% by weight in terms of the oxide of the rare earth element. If necessary, at least one of alumina and aluminum nitride is added in an amount of 1.0% by weight or less to form a raw material mixture to prepare a green body, and the obtained green body is degreased at a temperature of 180.
Atmospheric pressure sintering at 0 to 2100 ° C., the cooling rate of the sintered body from the above sintering temperature to the temperature at which the liquid phase formed during sintering by the above rare earth element solidifies is 100 ° C./hour.
It is characterized in that it is gradually cooled as follows. The obtained sintered body is ground and polished into a predetermined shape to manufacture the high thermal conductivity silicon nitride substrate used in the present invention.
【0028】上記製造方法において、窒化けい素粉末
に、さらにアルミナおよび窒化アルミニウムの少なくと
も一方を1.0重量%以下添加するとよい。In the above manufacturing method, it is preferable to add 1.0% by weight or less of at least one of alumina and aluminum nitride to the silicon nitride powder.
【0029】さらに窒化けい素粉末に、さらにTi,Z
r,Hf,V,Nb,Ta,Cr,Mo,Wの酸化物、
炭化物、窒化物、けい化物、硼化物からなる群より選択
される少なくとも1種を0.1〜3.0重量%添加する
とよい。In addition to silicon nitride powder, Ti, Z
oxides of r, Hf, V, Nb, Ta, Cr, Mo, W,
It is preferable to add 0.1 to 3.0% by weight of at least one selected from the group consisting of carbides, nitrides, silicides and borides.
【0030】上記製造方法によれば、窒化けい素結晶組
織中に希土類元素等を含む粒界相が形成され、気孔率が
2.5%以下、熱伝導率が60W/m・K以上、三点曲
げ強度が室温で650MPa以上の機械的特性および熱
伝導特性が共に優れた窒化けい素焼結体が得られる。According to the above manufacturing method, a grain boundary phase containing a rare earth element or the like is formed in the silicon nitride crystal structure, the porosity is 2.5% or less, the thermal conductivity is 60 W / m · K or more, and It is possible to obtain a silicon nitride sintered body having a point bending strength of 650 MPa or more at room temperature, which is excellent in both mechanical properties and heat conduction properties.
【0031】本発明において使用される高熱伝導性窒化
けい素基板の主成分となる窒化けい素粉末としては、焼
結性、強度および熱伝導率を考慮して、酸素含有量が
1.7重量%以下、好ましくは0.5〜1.5重量%、
Li,Na,K,Fe,Mg,Ca,Sr,Ba,M
n,Bなどの不純物陽イオン元素含有量が合計で0.3
重量%以下、好ましくは0.2重量%以下に抑制された
α相型窒化けい素を90重量%以上、好ましくは93重
量%以上含有し、平均粒径が1.0μm以下、好ましく
は0.4〜0.8μm程度の微細な窒化けい素粉末を使
用することができる。The silicon nitride powder which is the main component of the high thermal conductivity silicon nitride substrate used in the present invention has an oxygen content of 1.7 wt% in consideration of sinterability, strength and thermal conductivity. % Or less, preferably 0.5 to 1.5% by weight,
Li, Na, K, Fe, Mg, Ca, Sr, Ba, M
The total content of impurity cation elements such as n and B is 0.3.
It contains 90% by weight or more, preferably 93% by weight or more, of α-phase type silicon nitride suppressed to a weight% or less, preferably 0.2% by weight or less, and has an average particle size of 1.0 μm or less, preferably 0. Fine silicon nitride powder of about 4 to 0.8 μm can be used.
【0032】平均粒径が1.0μm以下の微細な原料粉
末を使用することにより、少量の焼結助剤であっても気
孔率が2.5%以下の緻密な焼結体を形成することが可
能であり、また焼結助剤が熱伝導特性を阻害するおそれ
も減少する。By using a fine raw material powder having an average particle size of 1.0 μm or less, it is possible to form a dense sintered body having a porosity of 2.5% or less even with a small amount of a sintering aid. It is also possible to reduce the risk of the sintering aid impairing the heat conduction characteristics.
【0033】またLi,Na,K,Fe,Ca,Mg,
Sr,Ba,Mn,Bの不純物陽イオン元素は熱伝導性
を阻害する物質となるため、60W/m・K以上の熱伝
導率を確保するためには、上記不純物陽イオン元素の含
有量は合計で0.3重量%以下とすることにより達成可
能である。特に同様の理由により、上記不純物陽イオン
元素の含有量は合計で0.2重量%以下とすることが、
さらに好ましい。ここで通常の窒化けい素焼結体を得る
ために使用される窒化けい素粉末には、特にFe,C
a,Mgが比較的に多く含有されているため、Fe,C
a,Mgの合計量が上記不純物陽イオン元素の合計含有
量の目安となる。Li, Na, K, Fe, Ca, Mg,
Impurity cation elements of Sr, Ba, Mn, and B are substances that impede thermal conductivity. Therefore, in order to ensure a thermal conductivity of 60 W / m · K or more, the content of the impurity cation elements is It can be achieved by setting the total to 0.3% by weight or less. Particularly, for the same reason, the total content of the above-mentioned impurity cation elements is 0.2% by weight or less,
More preferred. The silicon nitride powder used for obtaining the usual silicon nitride sintered body is particularly Fe, C.
Since a and Mg are contained in relatively large amounts, Fe and C
The total amount of a and Mg is a measure of the total content of the above impurity cation elements.
【0034】さらに、β相型と比較して焼結性に優れた
α相型窒化けい素を90重量%以上含有する窒化けい素
原料粉末を使用することにより、高密度の焼結体を製造
することができる。Further, by using a silicon nitride raw material powder containing 90% by weight or more of α-phase type silicon nitride, which is superior in sinterability as compared with the β-phase type, a high density sintered body is manufactured. can do.
【0035】また窒化けい素原料粉末に焼結助剤として
添加する希土類元素としては、Ho,Er,Yb,Y,
La,Sc,Pr,Ce,Nd,Dy,Sm,Gdなど
の酸化物もしくは焼結操作により、これらの酸化物とな
る物質が単独で、または2種以上の酸化物を組み合せた
ものを含んでもよいが、特に酸化ホルミウム(Ho2 O
3 ),酸化エルビウム(Er2 O3 )が好ましい。The rare earth elements added to the silicon nitride raw material powder as a sintering aid include Ho, Er, Yb, Y,
Depending on the oxide such as La, Sc, Pr, Ce, Nd, Dy, Sm, Gd or the sintering operation, these oxide substances may be used alone or in combination of two or more kinds. Good, but especially holmium oxide (Ho 2 O
3 ) and erbium oxide (Er 2 O 3 ) are preferred.
【0036】特に希土類元素としてランタノイド系列の
元素であるHo,Er,Ybを使用することにより、焼
結性あるいは高熱伝導化が良好になり、1850℃程度
の低温度領域においても十分に緻密な焼結体が得られ
る。したがって焼成装置の設備費およびランニングコス
トを低減できる効果も得られる。これらの焼結助剤は、
窒化けい素原料粉末と反応して液相を生成し、焼結促進
剤として機能する。In particular, by using lanthanoid series elements Ho, Er and Yb as the rare earth element, the sinterability or the high thermal conductivity is improved, and the firing is sufficiently dense even in the low temperature region of about 1850 ° C. A union is obtained. Therefore, the effect of reducing the equipment cost and running cost of the firing apparatus can be obtained. These sintering aids are
It reacts with the silicon nitride raw material powder to form a liquid phase and functions as a sintering accelerator.
【0037】上記焼結助剤の添加量は、酸化物換算で原
料粉末に対して2.0〜17.5重量%の範囲とする。
この添加量が2.0重量%未満の場合は、焼結体の緻密
化が不十分であり、特に希土類元素がランタノイド系元
素のように原子量が大きい元素の場合には、比較的低強
度で比較的に低熱伝導率の焼結体が形成される。一方、
添加量が17.5重量%を超える過量となると、過量の
粒界相が生成し、熱伝導率の低下や強度が低下し始める
ので上記範囲とする。特に同様の理由により4〜15重
量%とすることが望ましい。The amount of the above-mentioned sintering aid added is in the range of 2.0 to 17.5% by weight based on the raw material powder in terms of oxide.
If the added amount is less than 2.0% by weight, the densification of the sintered body is insufficient, and particularly when the rare earth element is an element having a large atomic weight such as a lanthanoid element, the strength is relatively low. A sintered body having a relatively low thermal conductivity is formed. on the other hand,
If the addition amount exceeds 17.5% by weight, an excessive amount of grain boundary phase is generated, and thermal conductivity and strength start to decrease, so the above range is set. Particularly, for the same reason, it is desirable that the amount is 4 to 15% by weight.
【0038】また上記製造方法において他の選択的な添
加成分として使用するTi,Zr,Hf,V,Nb,T
a,Cr,Mo,Wの酸化物,炭化物、窒化物、けい化
物、硼化物は、上記希土類元素の焼結促進剤の機能を促
進すると共に、結晶組織において分散強化の機能を果し
Si3 N4 焼結体の機械的強度を向上させるものであ
り、特に、Hf,Tiの化合物が好ましい。これらの化
合物の添加量が0.1重量%未満の場合においては添加
効果が不充分である一方、3.0重量%を超える過量と
なる場合には熱伝導率および機械的強度や電気絶縁破壊
強度の低下が起こるため、添加量は0.1〜3.0重量
%の範囲とする。特に0.2〜2重量%とすることが望
ましい。Further, Ti, Zr, Hf, V, Nb and T used as other selective addition components in the above manufacturing method.
The oxides, carbides, nitrides, suicides, and borides of a, Cr, Mo, and W promote the function of the above-mentioned rare earth element sintering promoter and, at the same time, function as a dispersion strengthener in the crystal structure of Si 3 It improves the mechanical strength of the N 4 sintered body, and a compound of Hf and Ti is particularly preferable. If the addition amount of these compounds is less than 0.1% by weight, the effect of addition is insufficient, while if it exceeds 3.0% by weight, the thermal conductivity, mechanical strength, and electrical breakdown Since the strength decreases, the addition amount is set to the range of 0.1 to 3.0% by weight. In particular, it is desirable that the content be 0.2 to 2% by weight.
【0039】また上記Ti,Zr,Hf等の化合物は窒
化けい素焼結体を黒色系に着色し不透明性を付与する遮
光剤としても機能する。そのため、特に光によって誤動
作を生じ易い集積回路等を搭載する回路基板を製造する
場合には、上記Ti等の化合物を適正に添加し、遮光性
に優れた窒化けい素基板とすることが望ましい。The compounds such as Ti, Zr, and Hf also function as a light-shielding agent for coloring the silicon nitride sintered body in a blackish color to impart opacity. Therefore, particularly when manufacturing a circuit board on which an integrated circuit or the like is likely to malfunction due to light, it is desirable to appropriately add the compound such as Ti to obtain a silicon nitride substrate having an excellent light shielding property.
【0040】さらに上記製造方法において、他の選択的
な添加成分としてのアルミナ(Al2 O3 )は、前記希
土類元素の焼結促進剤の機能を助長する役目を果すもの
であり、特に加圧焼結を行なう場合に著しい効果を発揮
するものである。このAl2 O3 の添加量が0.1重量
%未満の場合においては、より高温度での焼結が必要に
なる一方、1.0重量%を超える過量となる場合には過
量の粒界相を生成したり、または窒化けい素に固溶し始
め、熱伝導の低下が起こるため、添加量は1重量%以
下、好ましくは0.1〜0.75重量%の範囲とする。
特に強度、熱伝導率共に良好な性能を確保するためには
添加量を0.1〜0.5重量%の範囲とすることが望ま
しい。Further, in the above-mentioned manufacturing method, alumina (Al 2 O 3 ) as another optional additive component plays a role of promoting the function of the sintering promoter of the rare earth element, and particularly the pressure It exhibits a remarkable effect when sintering is performed. When the added amount of Al 2 O 3 is less than 0.1% by weight, it is necessary to sinter at a higher temperature, while when the added amount exceeds 1.0% by weight, an excessive amount of grain boundary is used. A phase is generated or a solid solution begins to form a solid solution in silicon nitride and the thermal conductivity is lowered. Therefore, the addition amount is 1% by weight or less, preferably 0.1 to 0.75% by weight.
In particular, in order to secure good performances in both strength and thermal conductivity, it is desirable that the addition amount be in the range of 0.1 to 0.5% by weight.
【0041】また、後述するAlNと併用する場合に
は、その合計添加量は1.0重量%以下にすることが望
ましい。When used in combination with AlN, which will be described later, it is desirable that the total addition amount be 1.0% by weight or less.
【0042】さらに他の添加成分としての窒化アルミニ
ウム(AlN)は焼結過程における窒化けい素の蒸発な
どを抑制するとともに、上記希土類元素の焼結促進剤と
しての機能をさらに助長する役目を果すものである。Further, aluminum nitride (AlN) as another additive component suppresses the evaporation of silicon nitride in the sintering process and also promotes the function of the above rare earth element as a sintering accelerator. Is.
【0043】AlNの添加量が0.1重量%未満(アル
ミナと併用する場合では0.05重量%未満)の場合に
おいては、より高温度での焼結が必要になる一方、1.
0重量%を超える過量となる場合には過量の粒界相を生
成したり、または窒化けい素に固溶し始め、熱伝導率の
低下が起こるため、添加量は0.1〜1.0重量%の範
囲とする。特に焼結性,強度,熱伝導率共に良好な性能
を確保するためには添加量を0.1〜0.5重量%の範
囲とすることが望ましい。なお前記Al2 O3と併用す
る場合には、AlNの添加量は0.05〜0.5重量%
の範囲が好ましい。When the amount of AlN added is less than 0.1% by weight (less than 0.05% by weight when used in combination with alumina), sintering at a higher temperature is required.
If the amount exceeds 0% by weight, an excessive amount of grain boundary phase is generated or begins to form a solid solution in silicon nitride, and the thermal conductivity decreases, so the addition amount is 0.1 to 1.0. The range is wt%. In particular, in order to secure good performances in terms of sinterability, strength, and thermal conductivity, it is desirable that the addition amount be in the range of 0.1 to 0.5% by weight. When used in combination with Al 2 O 3 , the addition amount of AlN is 0.05 to 0.5% by weight.
Is preferred.
【0044】また焼結体の気孔率は熱伝導率および強度
に大きく影響するため2.5%以下となるように製造す
る。気孔率が2.5%を超えると熱伝導の妨げとなり、
焼結体の熱伝導率が低下するとともに、焼結体の強度低
下が起こる。The porosity of the sintered body has a great influence on the thermal conductivity and the strength, so that the sintered body is manufactured so as to have a porosity of 2.5% or less. If the porosity exceeds 2.5%, it will hinder heat conduction,
The thermal conductivity of the sintered body decreases and the strength of the sintered body also decreases.
【0045】また、窒化けい素焼結体は組織的に窒化け
い素結晶と粒界相とから構成されるが、粒界相中の結晶
化合物相の割合は焼結体の熱伝導率に大きく影響し、本
発明において使用する窒化けい素焼結体においては粒界
相の20%以上とすることが必要であり、より好ましく
は50%以上が結晶相で占めることが望ましい。結晶相
が20%未満では熱伝導率が60W/m・K以上となる
ような放熱特性に優れ、かつ高温強度に優れた焼結体が
得られないからである。The silicon nitride sintered body is structurally composed of a silicon nitride crystal and a grain boundary phase. The proportion of the crystalline compound phase in the grain boundary phase has a great influence on the thermal conductivity of the sintered body. However, in the silicon nitride sintered body used in the present invention, it is necessary to make it 20% or more of the grain boundary phase, more preferably 50% or more of the crystal phase. This is because if the crystal phase is less than 20%, it is not possible to obtain a sintered body having excellent heat dissipation characteristics such as a thermal conductivity of 60 W / m · K or more and excellent high temperature strength.
【0046】さらに上記のように窒化けい素焼結体の気
孔率を2.5%以下にし、また窒化けい素結晶組織に形
成される粒界相の20%以上が結晶相で占めるようにす
るためには、窒化けい素成形体を温度1800〜210
0℃で2〜10時間程度、加圧焼結し、かつ焼結操作完
了直後における焼結体の冷却速度を毎時100℃以下に
して徐冷することが重要である。Further, as described above, the porosity of the silicon nitride sintered body is set to 2.5% or less, and 20% or more of the grain boundary phase formed in the silicon nitride crystal structure is occupied by the crystal phase. A silicon nitride compact at a temperature of 1800-210.
It is important to perform pressure sintering at 0 ° C. for about 2 to 10 hours and gradually cool the sintered body immediately after the completion of the sintering operation to 100 ° C. or less per hour.
【0047】焼結温度を1800℃未満とした場合に
は、焼結体の緻密化が不充分で気孔率が2.5vol%以上
になり機械的強度および熱伝導性が共に低下してしま
う。一方焼結温度が2100℃を超えると窒化けい素成
分自体が蒸発分解し易くなる。特に加圧焼結ではなく、
常圧焼結を実施した場合には、1800℃付近より窒化
けい素の分解蒸発が始まる。If the sintering temperature is less than 1800 ° C., the densification of the sintered body will be insufficient and the porosity will be 2.5 vol% or more, resulting in a decrease in both mechanical strength and thermal conductivity. On the other hand, if the sintering temperature exceeds 2100 ° C., the silicon nitride component itself tends to evaporate and decompose. Not especially pressure sintering,
When pressureless sintering is carried out, decomposition vaporization of silicon nitride begins at around 1800 ° C.
【0048】上記焼結操作完了直後における焼結体の冷
却速度は粒界相を結晶化させるために重要な制御因子で
あり、冷却速度が毎時100℃を超えるような急速冷却
を実施した場合には、焼結体組織の粒界相が非結晶質
(ガラス相)となり、焼結体に生成した液相が結晶相と
して粒界相に占める割合が20%未満となり、強度およ
び熱伝導性が共に低下してしまう。The cooling rate of the sintered body immediately after the completion of the above-mentioned sintering operation is an important control factor for crystallizing the grain boundary phase, and when the cooling rate is higher than 100 ° C./hour, rapid cooling is performed. The grain boundary phase of the sintered body structure becomes amorphous (glass phase), the liquid phase generated in the sintered body occupies less than 20% of the grain boundary phase as a crystal phase, and the strength and thermal conductivity are Both will decrease.
【0049】上記冷却速度を厳密に調整すべき温度範囲
は、所定の焼結温度(1800〜2100℃)から、前
記の焼結助剤の反応によって生成する液相が凝固するま
での温度範囲で充分である。ちなみに前記のような焼結
助剤を使用した場合の液相凝固点は概略1600〜15
00℃程度である。そして少なくとも焼結温度から上記
液相凝固温度に至るまでの焼結体の冷却速度を毎時10
0℃以下、好ましくは50℃以下、さらに好ましくは2
5℃以下に制御することにより、粒界相の20%以上、
特に好ましくは50%以上が結晶相になり、熱伝導率お
よび機械的強度が共に優れた焼結体が得られる。The temperature range in which the cooling rate should be strictly adjusted is a temperature range from a predetermined sintering temperature (1800 to 2100 ° C.) to the solidification of the liquid phase produced by the reaction of the above-mentioned sintering aid. Is enough. By the way, the liquidus freezing point when the above-mentioned sintering aid is used is approximately 1600 to 15
It is about 00 ° C. The cooling rate of the sintered body from at least the sintering temperature to the liquidus solidification temperature is set to 10 per hour.
0 ° C or lower, preferably 50 ° C or lower, more preferably 2
By controlling the temperature to 5 ° C or lower, 20% or more of the grain boundary phase,
Particularly preferably, 50% or more becomes a crystalline phase, and a sintered body excellent in both thermal conductivity and mechanical strength can be obtained.
【0050】本発明において使用する窒化けい素基板
は、例えば以下のようなプロセスを経て製造される。す
なわち前記所定の微細粒径を有し、また不純物含有量が
少ない微細な窒化けい素粉末に対して所定量の焼結助
剤、有機バインダ等の必要な添加剤および必要に応じて
Al2 O3 やAlN,Ti化合物等を加えて原料混合体
を調製し、次に得られた原料混合体を成形して所定形状
の成形体を得る。原料混合体の成形法としては、汎用の
金型プレス法、ドクターブレード法のようなシート成形
法などが適用できる。上記成形操作に引き続いて、成形
体を非酸化性雰囲気中で温度600〜800℃、または
空気中で温度400〜500℃で1〜2時間加熱して、
予め添加していた有機バインダ成分を充分に除去し、脱
脂する。次に脱脂処理された成形体を窒素ガス、水素ガ
スやアルゴンガスなどの不活性ガス雰囲気中で1800
〜2100℃の温度で所定時間雰囲気加圧焼結を行う。The silicon nitride substrate used in the present invention is manufactured through the following processes, for example. That is, with respect to the fine silicon nitride powder having a predetermined fine particle diameter and a small amount of impurities, a predetermined amount of a sintering aid, an organic binder, and other necessary additives and, if necessary, Al 2 O. A raw material mixture is prepared by adding 3 , 3 , AlN, Ti compounds and the like, and then the obtained raw material mixture is molded to obtain a molded product having a predetermined shape. As a forming method of the raw material mixture, a general-purpose die pressing method, a sheet forming method such as a doctor blade method, or the like can be applied. Following the above molding operation, the molded body is heated in a non-oxidizing atmosphere at a temperature of 600 to 800 ° C. or in air at a temperature of 400 to 500 ° C. for 1 to 2 hours,
The organic binder component added in advance is sufficiently removed and degreased. Next, the degreased molded body is subjected to 1800 in an atmosphere of an inert gas such as nitrogen gas, hydrogen gas or argon gas.
Atmosphere pressure sintering is performed at a temperature of 2100 ° C. for a predetermined time.
【0051】上記製法によって製造された窒化けい素焼
結体は、気孔率が2.5%以下、60W/m・K(25
℃)以上、さらには90W/m・K以上の熱伝導率を有
し、また三点曲げ強度が常温で650MPa以上と機械
的特性にも優れている。The silicon nitride sintered body produced by the above production method has a porosity of 2.5% or less and 60 W / m · K (25
(° C) or more, further 90 W / mK or more, and three-point bending strength of 650 MPa or more at room temperature, which is excellent in mechanical properties.
【0052】なお、低熱伝導性の窒化けい素に高熱伝導
性のSiC等を添加して焼結体全体としての熱伝導率を
60W/m・K以上にした窒化けい素系焼結体は本発明
の範囲には含まれない。しかしながら、熱伝導率が60
W/m・K以上である窒化けい素焼結体に高熱伝導性の
SiC等を複合させた窒化けい素系焼結体の場合には、
窒化けい素焼結体自体の熱伝導率が60W/m・K以上
である限り、本発明の範囲に含まれることは言うまでも
ない。It is to be noted that a silicon nitride-based sintered body obtained by adding SiC or the like having high thermal conductivity to silicon nitride having low thermal conductivity so that the thermal conductivity of the whole sintered body is 60 W / mK or more is obtained. It is not included in the scope of the invention. However, the thermal conductivity is 60
In the case of a silicon nitride-based sintered body in which a highly heat-conductive SiC or the like is combined with a silicon nitride sintered body having a W / m · K or more,
It goes without saying that as long as the thermal conductivity of the silicon nitride sintered body itself is 60 W / m · K or more, it falls within the scope of the present invention.
【0053】また上記窒化けい素焼結体から成る高熱伝
導性窒化けい素基板の厚さは、回路基板として使用した
場合の要求特性に応じて種々の厚さに設定されるが、回
路層の厚さの2倍以下にすることにより、基板自体を薄
くし、一定の熱伝導率を有する基板において、回路基板
としての放熱性を高めることができる。窒化けい素基板
の厚さが回路層の厚さの2倍を超えると、回路基板全体
の厚さが増加し熱抵抗が大きくなる。窒化けい素基板の
具体的な厚さは、0.25〜0.8mmの範囲である。特
に、この窒化けい素基板の厚さを0.5mm以下とするこ
とにより、回路基板全体の厚さを低減することができ、
回路基板の上下面間の熱抵抗差を、より効果的に減少さ
せることが可能になり、回路基板全体の放熱性を、より
改善することができる。The thickness of the high thermal conductivity silicon nitride substrate made of the above silicon nitride sintered body is set to various thicknesses according to the required characteristics when used as a circuit board. By making the thickness twice or less, the substrate itself can be thinned, and the heat dissipation as a circuit board can be improved in the substrate having a constant thermal conductivity. When the thickness of the silicon nitride substrate exceeds twice the thickness of the circuit layer, the thickness of the entire circuit substrate increases and the thermal resistance increases. The specific thickness of the silicon nitride substrate is in the range of 0.25 to 0.8 mm. In particular, by setting the thickness of this silicon nitride substrate to 0.5 mm or less, the thickness of the entire circuit board can be reduced,
The thermal resistance difference between the upper and lower surfaces of the circuit board can be more effectively reduced, and the heat dissipation of the entire circuit board can be further improved.
【0054】本発明に係る窒化けい素回路基板は、上記
のように製造した高熱伝導性窒化けい素基板の表面に、
導電性を有する回路層を一体に接合し、さらにこの回路
層を介して複数の半導体素子を搭載して製造される。The silicon nitride circuit board according to the present invention has the high thermal conductivity silicon nitride substrate manufactured as described above,
It is manufactured by integrally bonding conductive circuit layers and mounting a plurality of semiconductor elements via the circuit layers.
【0055】上記回路層の形成接合方法は、特に限定さ
れず、以下に説明する直接接合法,活性金属法またはメ
タライズ法などを適用することができる。The method of forming and joining the circuit layer is not particularly limited, and a direct joining method, an active metal method, a metallizing method, or the like described below can be applied.
【0056】直接接合法は、高熱伝導性窒化けい素基板
の表面に、厚さが0.5〜10μm程度の酸化層を形成
し、この酸化層を介して、回路層となる金属回路板を上
記窒化けい素基板に直接接合する方法である。ここで上
記金属回路板は、ろう材などの接合剤を使用せずに窒化
けい素基板表面に直接的に一体に接合される。すなわ
ち、金属回路板の成分と基板成分との共晶化合物を加熱
により発生せしめ、この共晶化合物を接合剤として両部
材が接合される。なお、この直接接合法はAl2 O3 な
どの酸化物系セラミックスについてのみ適用可能であ
り、窒化けい素基板にそのまま適用しても基板に対する
濡れ性が低いため、金属回路板の充分な接合強度が得ら
れない。In the direct bonding method, an oxide layer having a thickness of about 0.5 to 10 μm is formed on the surface of a high thermal conductivity silicon nitride substrate, and a metal circuit board to be a circuit layer is formed through this oxide layer. This is a method of directly bonding to the silicon nitride substrate. Here, the metal circuit board is directly and integrally bonded to the surface of the silicon nitride substrate without using a bonding agent such as a brazing material. That is, a eutectic compound of the components of the metal circuit board and the substrate component is generated by heating, and the two members are joined using this eutectic compound as a joining agent. Note that this direct bonding method can be applied only to oxide-based ceramics such as Al 2 O 3 , and even if it is directly applied to a silicon nitride substrate, it has low wettability to the substrate, so sufficient bonding strength of a metal circuit board is obtained. Can't get
【0057】そこで窒化けい素基板の表面に予め酸化層
を形成し、基板に対する濡れ性を高める必要がある。こ
の酸化層は上記高熱伝導性窒化けい素基板を、空気中な
どの酸化雰囲気中で温度1000〜1400℃程度で2
〜15時間加熱して形成される。この酸化層の厚さが
0.5μm未満の場合には、上記濡れ性の改善効果が少
ない一方、10μmを超えるように設定しても改善効果
が飽和するとともに、却って熱伝導率が低下し易くなる
ため、酸化層の厚さは0.5〜10μmの範囲、より好
ましくは1〜5μmの範囲とする。Therefore, it is necessary to previously form an oxide layer on the surface of the silicon nitride substrate to enhance the wettability with respect to the substrate. This oxide layer is formed on the silicon nitride substrate having high thermal conductivity at a temperature of about 1000 to 1400 ° C. in an oxidizing atmosphere such as air.
Formed by heating for ~ 15 hours. When the thickness of the oxide layer is less than 0.5 μm, the effect of improving the wettability is small, but even if it is set to exceed 10 μm, the improving effect is saturated and the thermal conductivity is likely to decrease. Therefore, the thickness of the oxide layer is in the range of 0.5 to 10 μm, more preferably 1 to 5 μm.
【0058】上記酸化層は、当初Si3 N4 基板成分の
酸化物であるSiO2 のみから構成されているが、加熱
による金属回路板の接合操作時において、Si3 N4 基
板に焼結助剤として添加されていた希土類元素酸化物が
酸化層方向に拡散移動する結果、希土類酸化物が酸化層
中に濃縮された構成となる。例えば焼結助剤としてY2
O3 を使用した場合には加熱接合操作後の酸化層は、Y
2 O3 を1〜20重量%程度含有するイットリアシリケ
ートなどのSiO2 −Y2 O3 化合物から構成されるよ
うになる。Although the oxide layer is initially composed only of SiO 2 , which is an oxide of the Si 3 N 4 substrate component, during the bonding operation of the metal circuit board by heating, the Si 3 N 4 substrate has a sintering aid. As a result of the rare earth element oxide added as the agent diffusing and moving toward the oxide layer, the rare earth oxide is concentrated in the oxide layer. For example, as a sintering aid, Y 2
When O 3 is used, the oxide layer after the heat bonding operation is Y
Comes to be composed of SiO 2 -Y 2 O 3 compound such yttria silicate containing about a 2 O 3 1 to 20% by weight.
【0059】また上記金属回路板を構成する金属として
は、銅,アルミニウム,鉄,ニッケル,クロム,銀,モ
リブデン,コバルトの単体またはその合金など、基板成
分との共晶化合物を生成し、直接接合法を適用できる金
属であれば特に限定されないが、特に導電性および価格
の観点から銅,アルミニウムまたはその合金が好まし
い。As a metal constituting the metal circuit board, a eutectic compound with a substrate component such as a simple substance of copper, aluminum, iron, nickel, chromium, silver, molybdenum, cobalt, or an alloy thereof is formed and directly contacted. There is no particular limitation as long as it is a metal to which legality can be applied, but copper, aluminum or an alloy thereof is particularly preferable from the viewpoint of conductivity and cost.
【0060】金属回路板(回路層)の厚さは、通電容量
等を勘案して決定されるが、窒化けい素基板の厚さを
0.25〜0.8mmの範囲とする一方、金属回路板の厚
さを0.2〜0.3mmの範囲に設定して両者を組み合せ
ると熱膨張差による変形などの影響を受けにくくなる。The thickness of the metal circuit board (circuit layer) is determined in consideration of the current-carrying capacity and the like, but the thickness of the silicon nitride substrate is set in the range of 0.25 to 0.8 mm, while the metal circuit board is formed. When the thickness of the plate is set in the range of 0.2 to 0.3 mm and the two are combined, the influence of deformation due to the difference in thermal expansion becomes less likely.
【0061】そして、金属回路板が銅回路板である場合
には、以下のように接合操作が実施される。すなわち酸
化層を形成した高熱伝導性窒化けい素基板の表面の所定
位置に、銅回路板を接触配置して基板方向に押圧した状
態で、銅の融点(1083℃)未満の温度で、かつ銅−
酸化銅の共晶温度(1065℃)以上に加熱し、生成し
たCu−O共晶化合物液相を接合剤として銅回路板が高
熱伝導性窒化けい素基板表面に直接的に接合される。こ
の直接接合法は、いわゆる銅直接接合法(DBC:Dire
ct Bonding Copper 法)である。さらに直接接合した銅
回路板の所定位置に複数の半導体素子(Si−チップ)
を半田接合して搭載することにより、本発明に係るSi
3 N4 回路基板が製造される。When the metal circuit board is a copper circuit board, the joining operation is carried out as follows. That is, a copper circuit board is placed in contact with a predetermined position on the surface of a silicon nitride substrate having a high thermal conductivity on which an oxide layer is formed, and is pressed toward the substrate at a temperature lower than the melting point (1083 ° C.) of copper and −
The copper circuit board is directly bonded to the surface of the high thermal conductivity silicon nitride substrate by heating it to a temperature higher than the eutectic temperature of copper oxide (1065 ° C.) and using the generated Cu—O eutectic compound liquid phase as a bonding agent. This direct bonding method is a so-called copper direct bonding method (DBC: Dire
ct Bonding Copper method). Further, a plurality of semiconductor elements (Si-chips) are provided at predetermined positions on the copper circuit board directly bonded.
By soldering and mounting the Si according to the present invention.
3 N 4 circuit boards are manufactured.
【0062】一方、金属回路板がアルミニウム回路板で
ある場合には、Si3 N4 基板表面にAl回路板を押圧
した状態でアルミニウム−けい素の共晶温度以上に加熱
し、生成したAl−Si共晶化合物を接合剤としてAl
回路板がSi3 N4 基板表面に直接的に接合される。そ
して直接接合したAl回路板の所定位置に複数の半導体
素子を半田接合して搭載することにより、本発明のSi
3 N4 回路基板が製造される。On the other hand, when the metal circuit board is an aluminum circuit board, the Al circuit board is heated to a temperature higher than the eutectic temperature of aluminum-silicon while pressing the Al circuit board against the surface of the Si 3 N 4 substrate, and the generated Al- Al using Si eutectic compound as a bonding agent
The circuit board is bonded directly to the Si 3 N 4 substrate surface. Then, a plurality of semiconductor elements are solder-bonded and mounted at predetermined positions on the Al circuit board which is directly bonded to the Si of the present invention.
3 N 4 circuit boards are manufactured.
【0063】このように直接接合法を使用して金属回路
板をSi3 N4 基板表面に直接接合し、さらに複数の半
導体素子を金属回路板上に搭載して形成した本発明に係
るSi3 N4 回路基板によれば、金属回路板とSi3 N
4 基板との間に、接着剤やろう材のような介在物が存在
しないため、両者間の熱抵抗が小さく、金属回路板上に
設けられた半導体素子の発熱を系外に迅速に放散させる
ことが可能である。As described above, the metal circuit board is directly bonded to the surface of the Si 3 N 4 substrate by using the direct bonding method, and further, a plurality of semiconductor elements are mounted on the metal circuit board to form Si 3 according to the present invention. According to N 4 circuit board, the metal circuit plate and the Si 3 N
4 Since there is no inclusion such as adhesive or brazing material between the board and the board, the heat resistance between the two is small, and the heat generated by the semiconductor element mounted on the metal circuit board is quickly dissipated outside the system. It is possible.
【0064】次に活性金属法による回路層の接合方法を
説明する。Next, a method of joining circuit layers by the active metal method will be described.
【0065】活性金属法では、Ti,Zr,Hfおよび
Nbから選択される少なくとも1種の活性金属を含有し
適切な組成比を有するAg−Cu−Ti系ろう材等で窒
化けい素基板表面に、厚さ20μm前後の活性金属ろう
材層を形成し、このろう材層を介して、銅回路板などの
金属回路板が接合される。活性金属は、基板に対するろ
う材の濡れ性を改善し、接合強度を高める作用を有す
る。活性金属ろう材の具体例としては、重量%で上記活
性金属を1〜10%,Cuを15〜35%,残部が実質
的にAgから成るろう材組成物が好適である。上記活性
金属ろう材層は、このろう材組成物を有機溶媒中に分散
して調製した接合用組成物ペーストを窒化けい素基板表
面にスクリーン印刷する等の方法で形成される。In the active metal method, an Ag-Cu-Ti-based brazing material containing at least one active metal selected from Ti, Zr, Hf and Nb and having an appropriate composition ratio is applied to the surface of the silicon nitride substrate. An active metal brazing material layer having a thickness of about 20 μm is formed, and a metal circuit board such as a copper circuit board is joined via the brazing material layer. The active metal has an effect of improving the wettability of the brazing material with respect to the substrate and increasing the bonding strength. As a specific example of the active metal brazing material, a brazing material composition in which the active metal is 1 to 10% by weight, Cu is 15 to 35%, and the balance is substantially Ag is preferable. The active metal brazing material layer is formed by a method such as screen-printing a bonding composition paste prepared by dispersing the brazing material composition in an organic solvent on the surface of the silicon nitride substrate.
【0066】そしてスクリーン印刷した活性金属ろう材
層上に、回路層となる金属回路板を接触配置した状態
で、真空中または不活性ガス雰囲気中で、例えばAg−
Cu共晶温度(780℃)以上で、かつ金属回路板の融
点(銅の場合は1083℃)以下の温度に加熱すること
により、金属回路板が活性金属ろう材層を介して窒化け
い素基板に一体に接合される。Then, in a state where a metal circuit board to be a circuit layer is placed in contact with the screen-printed active metal brazing material layer, in vacuum or in an inert gas atmosphere, for example, Ag--
By heating to a temperature not lower than the Cu eutectic temperature (780 ° C.) and not higher than the melting point of the metal circuit board (1083 ° C. in the case of copper), the metal circuit board is exposed to the active metal brazing material layer through the silicon nitride substrate. Is integrally joined to.
【0067】次に、メタライズ法による回路層の形成法
を説明する。メタライズ法では、例えばモリブデン(M
o)やタングステン(W)などの高融点金属とTiやそ
の化合物とを主成分とするメタライズ組成物を窒化けい
素基板表面に焼き付けて、厚さ15μm程度の回路層と
しての高融点金属メタライズ層を形成する方法である。
このメタライズ法により、回路層を形成する場合には、
メタライズ層表面にさらにNiやAuから成る厚さ3〜
5μm程度の金属めっき層を形成することが好ましい。
この金属めっき層を形成することにより、メタライズ層
の表面平滑性が改善され、半導体素子との密着性がより
改善されるとともに、半田濡れ性が向上するため、半田
を使用した半導体素子の接合強度をより高めることがで
きる。Next, a method of forming a circuit layer by the metallizing method will be described. In the metallization method, for example, molybdenum (M
o) or a refractory metal such as tungsten (W) and a metallized composition mainly containing Ti or a compound thereof are baked on the surface of the silicon nitride substrate to form a refractory metal metallized layer as a circuit layer having a thickness of about 15 μm. Is a method of forming.
When a circuit layer is formed by this metallizing method,
The surface of the metallized layer is made of Ni or Au and has a thickness of 3 to
It is preferable to form a metal plating layer having a thickness of about 5 μm.
By forming this metal plating layer, the surface smoothness of the metallized layer is improved, the adhesion with the semiconductor element is further improved, and the solder wettability is improved, so the bonding strength of the semiconductor element using solder is improved. Can be increased.
【0068】上記構成に係る窒化けい素回路基板によれ
ば、窒化けい素焼結体が本来的に有する高強度高靭性特
性に加えて特に熱伝導率を大幅に改善した高熱伝導性窒
化けい素基板表面に回路層を一体に接合し、さらに複数
の半導体素子を搭載して形成されている。したがって、
複数の素子を搭載するために回路基板を大型に形成した
場合においても、靭性値が高いため最大たわみ量を大き
く確保することができる。そのため、アッセンブリ工程
において回路基板の締め付け割れが発生せず、回路基板
を用いた半導体装置を高い製造歩留りで量産することが
可能になる。According to the silicon nitride circuit board having the above structure, in addition to the high-strength and toughness characteristics originally possessed by the silicon nitride sintered body, the high-thermal-conductivity silicon nitride board in which the thermal conductivity is greatly improved is provided. A circuit layer is integrally bonded to the surface, and a plurality of semiconductor elements are mounted on the surface. Therefore,
Even when a circuit board is formed in a large size for mounting a plurality of elements, the toughness value is high, so that a large maximum deflection amount can be secured. For this reason, the circuit board does not suffer from cracking in the assembly process, and semiconductor devices using the circuit board can be mass-produced with a high manufacturing yield.
【0069】さらに単一の窒化けい素基板表面に複数の
半導体素子を搭載して回路基板としているため、従来の
ように半導体素子毎に個別に回路基板を形成していた場
合と比較して、回路基板の総数を低減することが可能と
なり回路基板の実装工程を簡素化でき、半導体装置の製
造効率を高めることができる。Further, since a plurality of semiconductor elements are mounted on the surface of a single silicon nitride substrate to form a circuit board, compared with the conventional case where a circuit board is formed for each semiconductor element, It is possible to reduce the total number of circuit boards, simplify the circuit board mounting process, and improve the manufacturing efficiency of semiconductor devices.
【0070】また窒化けい素基板の靭性値が高いため、
熱サイクルによって基板に割れが発生することが少な
く、耐熱サイクル特性が著しく向上し、耐久性および信
頼性に優れた半導体装置を提供することができる。Since the toughness value of the silicon nitride substrate is high,
It is possible to provide a semiconductor device in which cracks are less likely to occur in a substrate due to heat cycle, heat cycle characteristics are remarkably improved, and durability and reliability are excellent.
【0071】さらに従来では達成されていない高い熱伝
導率を有する窒化けい素基板を使用しているため、高出
力化および高集積化を指向する半導体素子を搭載した場
合においても、熱抵抗特性の劣化が少なく、優れた放熱
性を発揮する。Furthermore, since a silicon nitride substrate having a high thermal conductivity, which has not been achieved in the past, is used, the thermal resistance characteristics of the semiconductor device can be improved even when a semiconductor device for high output and high integration is mounted. Shows excellent heat dissipation with little deterioration.
【0072】特に窒化けい素基板自体の機械的強度が優
れているため、要求される機械的強度特性を一定とした
場合に、他のセラミックス基板を使用した場合と比較し
て基板厚さをより低減することが可能となる。この基板
厚さを低減できることから熱抵抗値をより小さくでき、
放熱特性をさらに改善することができる。また要求され
る機械的特性に対して、従来より薄い基板でも充分に対
応可能となるため、回路基板の高密度実装も可能とな
り、半導体装置をより小型化することが可能となる。In particular, since the silicon nitride substrate itself is excellent in mechanical strength, when the required mechanical strength characteristics are kept constant, the substrate thickness can be made larger than that when other ceramic substrates are used. It becomes possible to reduce. Since the substrate thickness can be reduced, the thermal resistance value can be made smaller,
The heat dissipation characteristics can be further improved. Further, since it is possible to sufficiently meet the required mechanical characteristics even with a substrate thinner than before, it is possible to mount the circuit board at a high density and further downsize the semiconductor device.
【0073】[0073]
【発明の実施の形態】次に本発明の実施形態について以
下に示す実施例を参照して具体的に説明する。DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be specifically described with reference to the following examples.
【0074】実施例1〜3 酸素を1.3重量%、不純物陽イオン元素としてLi,
Na,K,Fe,Ca,Mg,Sr,Ba,Mn,Bを
合計で0.15重量%含有し、α相型窒化けい素97%
を含む平均粒径0.55μmの窒化けい素原料粉末に対
して、焼結助剤として平均粒径0.7μmのY2 O
3 (酸化イットリウム)粉末5重量%、平均粒径0.5
μmのAl2 O3 (アルミナ)粉末1.0重量%を添加
し、エチルアルコール中で24時間湿式混合した後に乾
燥して原料粉末混合体を調整した。次に得られた原料粉
末混合体に有機バインダを所定量添加して均一に混合し
た後に、1000kg/cm2 の成形圧力でプレス成形し、
長さ80mm×幅50mm×厚さ1〜5mmの成形体を多数製
作した。次に得られた成形体を700℃の雰囲気ガス中
において2時間脱脂した後に、この脱脂体を窒素ガス雰
囲気中7.5気圧にて1900℃で6時間保持し、緻密
化焼結を実施した後に、焼結炉に付設した加熱装置への
通電量を制御して焼結炉内温度が1500℃まで降下す
るまでの間における焼結体の冷却速度がそれぞれ50℃
/hrとなるように調整して焼結体を冷却し、さらに得ら
れた各焼結体を研摩加工してそれぞれ熱伝導率kが92
W/m・Kであり、厚さが0.4mm,0.6mm,0.8
mmである実施例1〜3用の窒化けい素基板を調製した。 Examples 1 to 3 1.3 wt% oxygen, Li as the impurity cation element,
Containing 0.15 wt% of Na, K, Fe, Ca, Mg, Sr, Ba, Mn and B in total, and 97% of α-phase type silicon nitride
With respect to the average particle size silicon nitride material powder of 0.55μm comprising, an average particle size of 0.7μm as a sintering aid Y 2 O
3 (yttrium oxide) powder 5% by weight, average particle size 0.5
1.0 wt% of Al 2 O 3 (alumina) powder of μm was added, wet-mixed in ethyl alcohol for 24 hours, and then dried to prepare a raw material powder mixture. Next, a predetermined amount of an organic binder was added to the obtained raw material powder mixture and uniformly mixed, and then press-molded at a molding pressure of 1000 kg / cm 2 ,
A large number of molded products having a length of 80 mm, a width of 50 mm and a thickness of 1 to 5 mm were manufactured. Next, the obtained molded body was degreased in an atmosphere gas at 700 ° C. for 2 hours, and then the degreased body was held in a nitrogen gas atmosphere at 7.5 atm at 1900 ° C. for 6 hours to perform densification sintering. After that, the cooling rate of the sintered body was 50 ° C. until the temperature inside the sintering furnace dropped to 1500 ° C. by controlling the amount of electricity supplied to the heating device attached to the sintering furnace.
/ Hr was adjusted to cool the sintered body, and each of the obtained sintered bodies was polished to obtain a thermal conductivity k of 92.
W / mK, thickness 0.4mm, 0.6mm, 0.8
mm silicon nitride substrates for Examples 1-3 were prepared.
【0075】次に図1に示すように各窒化けい素基板2
表面の回路層を形成する部位および裏面の銅板を接合す
る部位に、30wt%Ag−65%Cu−5%Tiろう
材をスクリーン印刷し乾燥して厚さ20μmの活性金属
ろう材層7a,7bを形成した。この活性金属ろう材層
7a,7bの所定位置に、無酸素銅から成る厚さ0.3
mmの銅回路板4と厚さ0.25mm値の裏銅板5とを接触
配置した状態で、真空中で温度850℃で10分間保持
して接合体とした。次に各接合体をエッチング処理する
ことにより、所定回路パターン(回路層)を形成した。
さらに2ヶ所の銅回路板4の中央部にそれぞれ半導体素
子6を半田接合して実施例1〜3に係る窒化けい素回路
基板1を多数製造した。Next, as shown in FIG. 1, each silicon nitride substrate 2
30 wt% Ag-65% Cu-5% Ti brazing filler metal is screen-printed on the portion where the front surface circuit layer is formed and the rear portion where the copper plate is joined, and the active metal brazing filler metal layers 7 a and 7 b having a thickness of 20 μm are dried. Was formed. At a predetermined position on the active metal brazing material layers 7a and 7b, a thickness of oxygen-free copper of 0.3
The copper circuit board 4 having a thickness of 0.25 mm and the back copper plate 5 having a thickness of 0.25 mm were placed in contact with each other, and held in vacuum at a temperature of 850 ° C. for 10 minutes to form a bonded body. Next, a predetermined circuit pattern (circuit layer) was formed by etching each bonded body.
Further, the semiconductor elements 6 were solder-bonded to the central portions of the copper circuit boards 4 at two locations to manufacture a large number of silicon nitride circuit boards 1 according to Examples 1 to 3.
【0076】比較例 実施例1〜3で使用した窒化けい素基板に代えて、熱伝
導率kが70W/m・Kであり厚さが0.8mmの窒化ア
ルミニウム(AlN)基板を使用した以外は実施例1〜
3と同様に活性金属法によって基板表面に銅回路板およ
び裏銅板を一体に接合して比較例に係る回路基板を製造
した。 Comparative Example Other than using the silicon nitride substrate used in Examples 1 to 3, an aluminum nitride (AlN) substrate having a thermal conductivity k of 70 W / mK and a thickness of 0.8 mm was used. Is Example 1
In the same manner as in No. 3, a copper circuit board and a back copper plate were integrally joined to the surface of the board by the active metal method to manufacture a circuit board according to a comparative example.
【0077】このようにして調製した実施例1〜3およ
び比較例に係る回路基板の最大たわみ量および抗折強度
を測定したところ、実施例1〜3に係る窒化けい素回路
基板1は、従来の窒化アルミニウム基板を使用した比較
例の回路基板と比較して2倍以上の最大たわみ量と抗折
強度とを有することが判明した。また窒化けい素基板の
厚さを低減するに伴って、さらにたわみ量および抗折強
度が改善されることも確認できた。さらに基板厚さの低
減化により、熱抵抗が減少するため、回路基板全体とし
ての放熱特性をさらに改善できることも確認できた。When the maximum deflection and bending strength of the circuit boards according to Examples 1 to 3 and the comparative example thus prepared were measured, the silicon nitride circuit boards 1 according to Examples 1 to 3 were It was found that the maximum deflection amount and bending strength were at least twice as high as the circuit board of the comparative example using the aluminum nitride substrate. It was also confirmed that as the thickness of the silicon nitride substrate was reduced, the amount of deflection and the bending strength were further improved. Further, it was confirmed that the thermal resistance is reduced due to the reduction of the board thickness, so that the heat dissipation characteristics of the entire circuit board can be further improved.
【0078】上記各実施例の回路基板をアッセンブリ工
程においてボードに実装したところ、締め付け割れが発
生せず、回路基板を用いた半導体装置を高い製造歩留り
で量産することができた。また複数の半導体素子6,6
を同一の窒化けい素基板2上に一括して搭載する構造で
あるため、半導体素子毎に個別に回路基板を形成する場
合と比較して、回路基板をコンパクト化できる上に、回
路基板の装置への組み込み回数も減少し、実装性を大幅
に改善することができた。When the circuit board of each of the above-described embodiments was mounted on the board in the assembly process, tightening cracks did not occur, and semiconductor devices using the circuit board could be mass-produced with a high manufacturing yield. In addition, a plurality of semiconductor elements 6, 6
Are collectively mounted on the same silicon nitride substrate 2, so that the circuit substrate can be made compact as compared with the case where the circuit substrate is individually formed for each semiconductor element, and the device for the circuit substrate is also provided. The number of integrations into the product has also been reduced, and the mountability has been greatly improved.
【0079】また各回路基板について−45℃から室温
(RT)まで加熱し、引き続き室温から+125℃まで
加熱した後に、室温を経て再び−45℃に冷却するまで
を1サイクルとする昇温−降温サイクルを繰り返して付
加し、基板部にクラック等が発生するまでのサイクル数
を測定する耐熱サイクル試験を実施したところ、実施例
1〜3の回路基板では1000サイクル経過後において
も、Si3 N4 基板の割れや金属回路板(Cu回路板)
の剥離が皆無であり、優れた耐熱サイクル特性を示すこ
とが判明した。一方、比較例の回路基板においては、1
00サイクルでクラックが発生し、耐久性が低いことが
確認された。Each circuit board is heated from −45 ° C. to room temperature (RT), then heated from room temperature to + 125 ° C., and then cooled again to −45 ° C. through room temperature, which is one cycle. A cycle was repeatedly added and a heat-resistant cycle test was conducted to measure the number of cycles until a crack or the like was generated in the substrate part. With the circuit boards of Examples 1 to 3, even after 1000 cycles, Si 3 N 4 Board cracks and metal circuit boards (Cu circuit boards)
It was found that no peeling was observed and the excellent heat cycle characteristics were exhibited. On the other hand, in the circuit board of the comparative example, 1
It was confirmed that cracks occurred at 00 cycles and the durability was low.
【0080】なお、図1に示すように裏銅板5に間隔を
おいて断面V字形の溝10を予め形成しておくことによ
って、ヒートサイクル時における裏銅板5の膨脹収縮を
ある程度吸収することが可能となる。そのため、複数の
素子6を搭載するために広面積の窒化けい素基板2を使
用して大型の回路基板1を形成した場合においても、ヒ
ートサイクルによる熱応力の発生が少なく、回路基板1
に反りを発生することも少ない。As shown in FIG. 1, the grooves 10 having a V-shaped cross section are preliminarily formed in the back copper plate 5 at intervals so that the expansion and contraction of the back copper plate 5 during the heat cycle can be absorbed to some extent. It will be possible. Therefore, even when the large-sized circuit board 1 is formed by using the wide-area silicon nitride substrate 2 for mounting the plurality of elements 6, the thermal stress due to the heat cycle is small and the circuit board 1
There is little occurrence of warpage.
【0081】実施例4 実施例1〜3において調製したSi3 N4 基板であり熱
伝導率kが92W/m・Kであり厚さがそれぞれ0.4
mm,0.6mm,0.8mmである各Si3 N4基板を酸化
炉中で温度1300℃で12時間加熱することにより、
基板の全表面を酸化し、厚さ2μmの酸化層を形成し
た。酸化層はSiO2 皮膜で形成される。 Example 4 The Si 3 N 4 substrate prepared in Examples 1 to 3 has a thermal conductivity k of 92 W / m · K and a thickness of 0.4.
By heating each Si 3 N 4 substrate having a size of 0.6 mm, 0.6 mm, and 0.8 mm in an oxidation furnace at a temperature of 1300 ° C. for 12 hours,
The entire surface of the substrate was oxidized to form an oxide layer having a thickness of 2 μm. The oxide layer is formed of a SiO 2 film.
【0082】次に酸化層を形成した各Si3 N4 基板表
面側に、厚さ0.3mmのタフピッチ電解銅から成る銅回
路板を接触配置する一方、背面側に厚さ0.25mmのタ
フピッチ銅から成る銅回路板を裏当て材として接触配置
させて積層体とし、この積層体を窒素ガス雰囲気に調整
した温度1075℃の加熱炉に挿入して1分間加熱する
ことにより、各Si3 N4 基板の両面に銅回路板を直接
接合し、さらに2個の半導体素子を半田接合したSi3
N4 回路基板をそれぞれ調製した。Next, a copper circuit board made of tough pitch electrolytic copper having a thickness of 0.3 mm is placed in contact with the surface side of each Si 3 N 4 substrate on which an oxide layer has been formed, while a tough pitch of 0.25 mm thickness is provided on the back side. A copper circuit board made of copper is placed as a backing material in contact with each other to form a laminated body, and the laminated body is inserted into a heating furnace adjusted to a nitrogen gas atmosphere at a temperature of 1075 ° C. and heated for 1 minute to obtain each Si 3 N 2. Si 3 in which copper circuit boards are directly bonded to both sides of 4 boards, and two semiconductor elements are solder bonded
N 4 circuit boards were prepared respectively.
【0083】各Si3 N4 回路基板1aは、図2に示す
ようにSi3 N4 基板2の全表面にSiO2 から成る酸
化層3が形成されており、Si3 N4 基板2の表面側に
金属回路板としての銅回路板4が直接接合される一方、
背面側に裏銅板としての銅回路板5が同様に直接接合さ
れ、さらに表面側の銅回路板4の所定位置2ヶ所に図示
しない半田層を介して半導体素子6がそれぞれ一体に接
合された構造を有する。なおSi3 N4 基板2の両面に
銅回路板4,5を接合した場合、裏銅板としての銅回路
板5は放熱促進および反り防止に寄与するので有効であ
る。[0083] Each Si 3 N 4 circuit board 1a is oxidized layer 3 made of SiO 2 is formed on the entire surface the Si 3 N 4 substrate 2 as shown in FIG. 2, Si 3 N 4 surface of the substrate 2 While the copper circuit board 4 as a metal circuit board is directly joined to the side,
Similarly, a copper circuit board 5 as a back copper board is directly joined to the back side, and semiconductor elements 6 are integrally joined to two predetermined positions of the copper circuit board 4 on the front side via solder layers not shown. Have. When the copper circuit boards 4 and 5 are bonded to both surfaces of the Si 3 N 4 substrate 2, the copper circuit board 5 as the back copper plate contributes to promotion of heat dissipation and prevention of warpage, which is effective.
【0084】上記のように直接接合法によって回路層を
形成した実施例4に係るSi3 N4回路基板の最大たわ
み量は0.7〜1.6mmの範囲であり、また抗折強度は
550〜900MPaの範囲であり、実施例1〜3のよ
うに活性金属法で回路層を形成した場合と同等の特性値
が得られた。また耐熱サイクル試験において1000サ
イクル経過後においてもSi3 N4 基板の割れや金属回
路板の剥離が皆無であり、優れた耐熱サイクル特性を示
した。The maximum deflection of the Si 3 N 4 circuit board according to Example 4 in which the circuit layer was formed by the direct bonding method as described above was in the range of 0.7 to 1.6 mm, and the bending strength was 550. It was in the range of up to 900 MPa, and a characteristic value equivalent to that when the circuit layer was formed by the active metal method as in Examples 1 to 3 was obtained. Further, in the heat resistance cycle test, there was no cracking of the Si 3 N 4 substrate or peeling of the metal circuit board even after 1000 cycles, and excellent heat resistance cycle characteristics were exhibited.
【0085】実施例5 図3に示すように、実施例1〜3において調製したSi
3 N4 基板であり熱伝導率kが92W/m・Kであり厚
さがそれぞれ0.4mm,0.6mm,0.8mmであるSi
3 N4 基板2の表面に、モリブデン(Mo)と酸化チタ
ン(TiO2)との混合粉末に適量のバインダと溶剤と
を加えてペースト状にしたものをスクリーン印刷し、加
熱焼成して厚さ15μmの高融点金属メイタライズ層8
を形成した。さらにメタライズ層8の上に無電解めっき
法により厚さ3μmのNiめっき層9を形成し、所定パ
ターンを有する回路層とした。次に回路層上の2ヶ所に
半導体素子6を半田付けにより接合して実施例5に係る
窒化けい素回路基板1bを多数製造した。 Example 5 As shown in FIG. 3, Si prepared in Examples 1 to 3
Si that is a 3 N 4 substrate and has a thermal conductivity k of 92 W / m · K and a thickness of 0.4 mm, 0.6 mm, and 0.8 mm, respectively.
On the surface of the 3 N 4 substrate 2, a mixed powder of molybdenum (Mo) and titanium oxide (TiO 2 ) to which a suitable amount of a binder and a solvent was added to form a paste was screen-printed and heated to a thickness. High melting point metal materization layer 8 of 15 μm
Was formed. Further, a Ni plating layer 9 having a thickness of 3 μm was formed on the metallized layer 8 by an electroless plating method to form a circuit layer having a predetermined pattern. Next, the semiconductor element 6 was joined to the two places on the circuit layer by soldering to manufacture many silicon nitride circuit boards 1b according to the fifth embodiment.
【0086】上記のようにメタライズ法によって回路層
を形成した実施例5に係るSi3 N4 回路基板の最大た
わみ量は1.0〜1.8mmの範囲であり、また抗折強度
は650〜950MPaの範囲であり、実施例1〜3の
ように活性金属法で回路層を形成した場合と同等の特性
値が得られた。また耐熱サイクル試験において1000
サイクル経過後においてもSi3 N4 基板の割れや回路
層(メタライズ層)8の剥離が皆無であり、めっき処理
を施した回路基板においても優れた耐熱サイクル特性を
示した。The maximum amount of deflection of the Si 3 N 4 circuit board according to Example 5 in which the circuit layer was formed by the metallizing method as described above was in the range of 1.0 to 1.8 mm, and the bending strength was 650 to 650. It was in the range of 950 MPa, and a characteristic value equivalent to that when the circuit layer was formed by the active metal method as in Examples 1 to 3 was obtained. In the heat resistance cycle test, 1000
There was no cracking of the Si 3 N 4 substrate or peeling of the circuit layer (metallized layer) 8 even after the lapse of cycles, and the circuit substrate subjected to the plating treatment also showed excellent heat resistance cycle characteristics.
【0087】次に種々の組成および特性値を有する他の
窒化けい素基板を使用した回路基板の実施形態について
以下に示す実施例6を参照して具体的に説明する。Next, an embodiment of a circuit board using another silicon nitride substrate having various compositions and characteristic values will be specifically described with reference to Example 6 shown below.
【0088】実施例6 まず回路基板の構成材となる各種窒化けい素基板を以下
の手順で製造した。 Example 6 First, various silicon nitride substrates as constituent materials of a circuit board were manufactured by the following procedure.
【0089】すなわち酸素を1.3重量%、前記不純物
陽イオン元素を合計で0.15重量%含有し、α相型窒
化けい素97%を含む平均粒径0.55μmの窒化けい
素原料粉末に対して、表1〜3に示すように、焼結助剤
としてのY2 O3 ,Ho2 O3 などの希土類酸化物と、
必要に応じてTi,Hf化合物,Al2 O3粉末,Al
N粉末とを添加し、エチルアルコール中で窒化けい素製
ボールを用いて72時間湿式混合した後に乾燥して原料
粉末混合体をそれぞれ調整した。次に得られた各原料粉
末混合体に有機バインダを所定量添加して均一に混合し
た後に、1000kg/cm2 の成形圧力でプレス成形し、
各種組成を有する成形体を多数製作した。次に得られた
各成形体を700℃の雰囲気ガス中において2時間脱脂
した後に、この脱脂体を表1〜3に示す焼結条件で緻密
化焼結を実施した後に、焼結炉に付設した加熱装置への
通電量を制御して焼結炉内温度が1500℃まで降下す
るまでの間における焼結体の冷却速度がそれぞれ表1〜
3に示す値となるように調整して焼結体を冷却し、それ
ぞれ試料1〜51に係る窒化けい素焼結体を調製した。That is, a silicon nitride raw material powder having an average particle diameter of 0.55 μm, containing 1.3% by weight of oxygen, 0.15% by weight of the impurity cation elements in total, and 97% of α-phase type silicon nitride. On the other hand, as shown in Tables 1 to 3 , rare earth oxides such as Y 2 O 3 and Ho 2 O 3 as sintering aids,
If necessary, Ti, Hf compound, Al 2 O 3 powder, Al
N powder was added, and the mixture was wet-mixed in ethyl alcohol for 72 hours using a silicon nitride ball and then dried to prepare raw material powder mixtures. Next, a predetermined amount of an organic binder was added to each of the obtained raw material powder mixtures and uniformly mixed, followed by press molding at a molding pressure of 1000 kg / cm 2 .
Many molded articles having various compositions were manufactured. Next, after degreasing each of the obtained compacts in an atmospheric gas at 700 ° C. for 2 hours, the degreased compacts were densified and sintered under the sintering conditions shown in Tables 1 to 3, and then attached to a sintering furnace. The cooling rate of the sintered body until the temperature inside the sintering furnace drops to 1500 ° C. by controlling the amount of electricity supplied to the heating device
The sintered body was cooled by adjusting it to the value shown in No. 3, and the silicon nitride sintered bodies of Samples 1 to 51 were prepared.
【0090】こうして得た試料1〜51に係る各窒化け
い素焼結体について気孔率、熱伝導率(25℃)、室温
での三点曲げ強度の平均値を測定した。さらに、各焼結
体についてX線回折法によって粒界相に占める結晶相の
割合(面積比)を測定し、下記表1〜3に示す結果を得
た。The average values of porosity, thermal conductivity (25 ° C.), and three-point bending strength at room temperature were measured for each of the silicon nitride sintered bodies of Samples 1 to 51 thus obtained. Further, the ratio (area ratio) of the crystal phase in the grain boundary phase was measured for each sintered body by the X-ray diffraction method, and the results shown in Tables 1 to 3 below were obtained.
【0091】[0091]
【表1】 [Table 1]
【0092】[0092]
【表2】 [Table 2]
【0093】[0093]
【表3】 [Table 3]
【0094】表1〜3に示す結果から明らかなように試
料1〜51に係る窒化けい素焼結体においては、原料組
成を適正に制御し、従来例と比較して緻密化焼結完了直
後における焼結体の冷却速度を従来より低く設定してい
るため、粒界相に結晶相を含み、結晶相の占める割合が
高い程、高熱伝導率を有する放熱性の高い高強度窒化け
い素焼結体が得られた。As is clear from the results shown in Tables 1 to 3, in the silicon nitride sintered bodies according to Samples 1 to 51, the raw material composition was appropriately controlled, and immediately after the densification and sintering was completed as compared with the conventional example. Since the cooling rate of the sintered body is set lower than before, the higher the ratio of the crystal phase in the grain boundary phase and the higher the proportion of the crystal phase, the higher the heat dissipation and the high strength silicon nitride sintered body with high heat dissipation. was gotten.
【0095】これに対して酸素を1.3〜1.5重量
%,前記不純物陽イオン元素を合計で0.13〜0.1
6重量%含有し、α相型窒化けい素を93%含む平均粒
径0.60μmの窒化けい素原料粉末を用い、この窒化
けい素粉末に対してY2 O3 (酸化イットリウム)粉末
を3〜6重量と、アルミナ粉末を1.3〜1.6重量%
添加した原料粉末を成形,脱脂後、1900℃で6時間
焼結し、炉冷(冷却速度:毎時400℃)して得た焼結
体の熱伝導率は25〜28W/m・Kと低く、従来の一
般的な製法によって製造された窒化けい素焼結体の熱伝
導率に近い値になった。On the other hand, 1.3 to 1.5% by weight of oxygen and 0.13 to 0.1% by weight of the above impurity cation elements are included.
A silicon nitride raw material powder containing 6% by weight and containing 93% of α-phase type silicon nitride and having an average particle size of 0.60 μm was used, and 3% of Y 2 O 3 (yttrium oxide) powder was added to the silicon nitride powder. ~ 6 wt% and 1.3-1.6 wt% alumina powder
The added raw material powder is molded and degreased, then sintered at 1900 ° C. for 6 hours and cooled in a furnace (cooling rate: 400 ° C./hour). The thermal conductivity was close to that of the silicon nitride sintered body manufactured by the conventional general manufacturing method.
【0096】次に得られた試料1〜51に係る各窒化け
い素焼結体を研磨加工することにより、実施例1〜5と
同様に、厚さ0.4mm,0.6mm,0.8mmの窒化けい
素基板をそれぞれ調製した。次に調製した各窒化けい素
基板の表面に、実施例1〜3と同様に活性金属法を使用
して銅回路板等を一体に接合することにより図1に示す
ような実施例6に係る窒化けい素回路基板をそれぞれ調
製した。Next, by polishing each of the obtained silicon nitride sintered bodies according to Samples 1 to 51, the thickness of 0.4 mm, 0.6 mm and 0.8 mm was obtained in the same manner as in Examples 1 to 5. Each silicon nitride substrate was prepared. Next, according to Example 6 as shown in FIG. 1, a copper circuit board or the like is integrally bonded to the surface of each silicon nitride substrate prepared by using the active metal method as in Examples 1 to 3. Each silicon nitride circuit board was prepared.
【0097】また各窒化けい素基板の表面に、実施例4
と同様にDBC法を使用して銅回路板等を直接接合する
ことにより、図2に示すような実施例6に係る窒化けい
素回路基板をそれぞれ調製した。In addition, Example 4 was formed on the surface of each silicon nitride substrate.
By directly joining a copper circuit board and the like using the DBC method in the same manner as in, a silicon nitride circuit board according to Example 6 as shown in FIG. 2 was prepared.
【0098】さらに各窒化けい素基板の表面に、実施例
5と同様にメタライズ法を使用して回路層を形成するこ
とにより、図3に示すような実施例6に係る窒化けい素
回路基板をそれぞれ調製した。Further, by forming a circuit layer on the surface of each silicon nitride substrate by using the metallizing method as in the fifth embodiment, the silicon nitride circuit substrate according to the sixth embodiment as shown in FIG. 3 is obtained. Each was prepared.
【0099】上記のように活性金属法,DBC法,メタ
ライズ法によって回路層を形成した実施例6に係る各S
i3 N4 回路基板の最大たわみ量,抗折強度は実施例1
〜5と同等以上であり、また耐熱サイクル試験において
1000サイクル経過後においてもSi3 N4 基板の割
れや回路層の剥離は皆無であり、優れた耐熱サイクル特
性が得られた。Each S according to the sixth embodiment in which the circuit layer is formed by the active metal method, the DBC method, and the metallizing method as described above.
The maximum deflection amount and bending strength of the i 3 N 4 circuit board are shown in Example 1.
5 or more, and there was no cracking of the Si 3 N 4 substrate or peeling of the circuit layer even after 1000 cycles in the heat resistance cycle test, and excellent heat resistance cycle characteristics were obtained.
【0100】[0100]
【発明の効果】以上説明の通り、本発明に係る窒化けい
素回路基板によれば、窒化けい素焼結体が本来的に有す
る高強度高靭性特性に加えて特に熱伝導率を大幅に改善
した高熱伝導性窒化けい素基板表面に回路層を一体に接
合し、さらに複数の半導体素子を搭載して形成されてい
る。したがって、複数の素子を搭載するために回路基板
を大型に形成した場合においても、靭性値が高いため最
大たわみ量を大きく確保することができる。そのため、
アッセンブリ工程において回路基板の締め付け割れが発
生せず、回路基板を用いた半導体装置を高い製造歩留り
で量産することが可能になる。As described above, according to the silicon nitride circuit board of the present invention, in addition to the high strength and high toughness characteristic inherent to the silicon nitride sintered body, the thermal conductivity is greatly improved. A circuit layer is integrally bonded to the surface of a silicon nitride substrate having high thermal conductivity, and a plurality of semiconductor elements are mounted on the circuit layer. Therefore, even when the circuit board is formed in a large size to mount a plurality of elements, the toughness value is high, so that a large maximum deflection amount can be secured. for that reason,
It is possible to mass-produce a semiconductor device using a circuit board with a high manufacturing yield without causing a tightening crack of the circuit board in the assembly process.
【0101】さらに1枚の窒化けい素基板表面に複数の
半導体素子を搭載して回路基板としているため、従来の
ように半導体素子毎に個別に回路基板を形成していた場
合と比較して、回路基板の総数を低減することが可能と
なり回路基板の実装工程を簡素化でき、半導体装置の製
造効率を高めることができる。Further, since a plurality of semiconductor elements are mounted on the surface of one silicon nitride substrate to form a circuit board, compared to the conventional case where a circuit board is formed for each semiconductor element, It is possible to reduce the total number of circuit boards, simplify the circuit board mounting process, and improve the manufacturing efficiency of semiconductor devices.
【0102】また窒化けい素基板の靭性値が高いため、
熱サイクルによって基板に割れが発生することが少な
く、耐熱サイクル特性が著しく向上し、耐久性および信
頼性に優れた半導体装置を提供することができる。Further, since the toughness value of the silicon nitride substrate is high,
It is possible to provide a semiconductor device in which cracks are less likely to occur in a substrate due to heat cycle, heat cycle characteristics are remarkably improved, and durability and reliability are excellent.
【0103】さらに従来では達成されていない高い熱伝
導率を有する窒化けい素基板を使用しているため、高出
力化および高集積化を指向する半導体素子を搭載した場
合においても、熱抵抗特性の劣化が少なく、優れた放熱
性を発揮する。Further, since a silicon nitride substrate having a high thermal conductivity, which has not been achieved in the past, is used, even when a semiconductor element aiming at high output and high integration is mounted, the thermal resistance characteristic is improved. Shows excellent heat dissipation with little deterioration.
【0104】特に窒化けい素基板自体の機械的強度が優
れているため、要求される機械的強度特性を一定とした
場合に、他のセラミックス基板を使用した場合と比較し
て基板厚さをより低減することが可能となる。この基板
厚さを低減できることから熱抵抗値をより小さくでき、
放熱特性をさらに改善することができる。また要求され
る機械的特性に対して、従来より薄い基板でも充分に対
応可能となるため、回路基板の高密度実装も可能とな
り、半導体装置をより小型化することが可能となる。In particular, since the silicon nitride substrate itself is excellent in mechanical strength, when the required mechanical strength characteristics are kept constant, the substrate thickness can be made larger than that when other ceramic substrates are used. It becomes possible to reduce. Since the substrate thickness can be reduced, the thermal resistance value can be made smaller,
The heat dissipation characteristics can be further improved. Further, since it is possible to sufficiently meet the required mechanical characteristics even with a substrate thinner than before, it is possible to mount the circuit board at a high density and further downsize the semiconductor device.
【図1】本発明に係る窒化けい素回路基板の一実施例を
示す断面図。FIG. 1 is a cross-sectional view showing an embodiment of a silicon nitride circuit board according to the present invention.
【図2】本発明に係る窒化けい素回路基板の他の実施例
を示す断面図。FIG. 2 is a sectional view showing another embodiment of the silicon nitride circuit board according to the present invention.
【図3】メタライズ法によって回路層を形成した回路基
板の断面図。FIG. 3 is a sectional view of a circuit board on which a circuit layer is formed by a metallizing method.
1,1a,1b 窒化けい素回路基板(Si3 N4 回路
基板) 2 窒化けい素(Si3 N4 )基板 3 酸化層(SiO2 皮膜) 4 金属回路板(Cu回路板),回路層 5 金属回路板(裏銅板) 6 半導体素子(チップ) 7a,7b 活性金属ろう材層 8 高融点金属メタライズ層 9 金属めっき層(Niめっき層) 10 溝1, 1a, 1b Silicon nitride circuit board (Si 3 N 4 circuit board) 2 Silicon nitride (Si 3 N 4 ) board 3 Oxide layer (SiO 2 film) 4 Metal circuit board (Cu circuit board), Circuit layer 5 Metal circuit board (back copper plate) 6 Semiconductor element (chip) 7a, 7b Active metal brazing material layer 8 Refractory metal metallization layer 9 Metal plating layer (Ni plating layer) 10 Groove
───────────────────────────────────────────────────── フロントページの続き (72)発明者 小松 通泰 神奈川県横浜市鶴見区末広町2の4 株式 会社東芝京浜事業所内 (72)発明者 水野谷 信幸 神奈川県横浜市鶴見区末広町2の4 株式 会社東芝京浜事業所内 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Mitsuyasu Komatsu 4-4 shares, 2 Suehiro-cho, Tsurumi-ku, Yokohama-shi, Kanagawa Toshiba Keihin Office (72) Inventor Nobuyuki Mizutani 4 shares, 2 Suehiro-cho, Tsurumi-ku, Yokohama-shi, Kanagawa Company Toshiba Keihin Office
Claims (9)
17.5重量%、不純物陽イオン元素としてのLi,N
a,K,Fe,Ca,Mg,Sr,Ba,Mn,Bを合
計で0.3重量%以下含有し、熱伝導率が60W/m・
K以上である高熱伝導性窒化けい素基板に回路層を接合
した回路基板であり、上記高熱伝導性窒化けい素基板上
に回路層を介して複数の半導体素子を搭載したことを特
徴とする窒化けい素回路基板。1. A rare earth element converted into an oxide of 2.0 to 2.0.
17.5 wt%, Li, N as impurity cation element
a, K, Fe, Ca, Mg, Sr, Ba, Mn, and B are contained in a total amount of 0.3 wt% or less, and the thermal conductivity is 60 W / m.
A circuit board in which a circuit layer is bonded to a high-thermal-conductivity silicon nitride substrate having a temperature of K or more, wherein a plurality of semiconductor elements are mounted on the high-thermal-conductivity silicon nitride substrate via the circuit layer. Silicon circuit board.
17.5重量%、不純物陽イオン元素としてのLi,N
a,K,Fe,Ca,Mg,Sr,Ba,Mn,Bを合
計で0.3重量%以下含有し、窒化けい素結晶および粒
界相から成るとともに粒界相中における結晶化合物相の
粒界相全体に対する割合が20%以上であり、熱伝導率
が60W/m・K以上である高熱伝導性窒化けい素基板
に回路層を接合した回路基板であり、上記高熱伝導性窒
化けい素基板上に回路層を介して複数の半導体素子を搭
載したことを特徴とする窒化けい素回路基板。2. A rare earth element converted into an oxide of 2.0 to.
17.5 wt%, Li, N as impurity cation element
a, K, Fe, Ca, Mg, Sr, Ba, Mn, and B in a total amount of 0.3 wt% or less, and is composed of a silicon nitride crystal and a grain boundary phase, and a grain of a crystalline compound phase in the grain boundary phase. A circuit board in which a circuit layer is bonded to a high thermal conductivity silicon nitride substrate having a ratio of 20% or more with respect to the entire phase and a thermal conductivity of 60 W / mK or more, and the high thermal conductivity silicon nitride substrate. A silicon nitride circuit board having a plurality of semiconductor elements mounted thereon via a circuit layer.
素結晶および粒界相から成るとともに粒界相中における
結晶化合物相の粒界相全体に対する割合が50%以上で
ある窒化けい素焼結体から成ることを特徴とする請求項
2記載の窒化けい素回路基板。3. A high-thermal-conductivity silicon nitride substrate is composed of silicon nitride crystals and a grain boundary phase, and the ratio of the crystal compound phase in the grain boundary phase to the whole grain boundary phase is 50% or more. The silicon nitride circuit board according to claim 2, wherein the silicon nitride circuit board comprises a body.
度が650MPa以上であることを特徴とする請求項1
記載の窒化けい素回路基板。4. The three-point bending strength of the high thermal conductivity silicon nitride substrate is 650 MPa or more.
The described silicon nitride circuit board.
層の厚さの2倍以下であることを特徴とする請求項1記
載の窒化けい素回路基板。5. The silicon nitride circuit board according to claim 1, wherein the thickness of the high thermal conductive silicon nitride board is not more than twice the thickness of the circuit layer.
90W/m・K以上であることを特徴とする請求項1記
載の窒化けい素回路基板。6. The silicon nitride circuit board according to claim 1, wherein the high thermal conductivity silicon nitride substrate has a thermal conductivity of 90 W / m · K or more.
路板が表面に酸化層を有する高熱伝導性窒化けい素基板
上に接合されていることを特徴とする請求項1記載の窒
化けい素回路基板。7. The silicon nitride according to claim 1, wherein the circuit layer is a metal circuit board, and the metal circuit board is bonded onto a high thermal conductive silicon nitride substrate having an oxide layer on the surface thereof. Elementary circuit board.
r,HfおよびNbから選択される少なくとも1種の活
性金属を含有する活性金属ろう材層を介して上記金属回
路板が高熱伝導性窒化けい素基板上に接合されているこ
とを特徴とする請求項1記載の窒化けい素回路基板。8. The circuit layer is a metal circuit board, Ti, Z
The metal circuit board is bonded onto a high thermal conductivity silicon nitride substrate through an active metal brazing material layer containing at least one active metal selected from r, Hf and Nb. Item 1. A silicon nitride circuit board according to item 1.
ることを特徴とする請求項1記載の窒化けい素回路基
板。9. The silicon nitride circuit board according to claim 1, wherein the circuit layer comprises a refractory metallized layer.
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JP15820795 | 1995-06-23 | ||
JP7-158207 | 1995-06-23 | ||
JP34423595A JP2772273B2 (en) | 1995-06-23 | 1995-12-28 | Silicon nitride circuit board |
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JPH0969590A true JPH0969590A (en) | 1997-03-11 |
JP2772273B2 JP2772273B2 (en) | 1998-07-02 |
Family
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JPH11236270A (en) * | 1998-02-25 | 1999-08-31 | Kyocera Corp | Silicon nitride substrate and its manufacture |
JP2000049257A (en) * | 1998-07-30 | 2000-02-18 | Kyocera Corp | Head radiation circuit board |
JP2001168482A (en) * | 1999-09-28 | 2001-06-22 | Toshiba Corp | Ceramics circuit substrate |
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JP2009520344A (en) * | 2005-12-19 | 2009-05-21 | キュラミーク エレクトロニクス ゲーエムベーハー | Metal-ceramic substrate |
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WO2008078788A1 (en) | 2006-12-26 | 2008-07-03 | Kyocera Corporation | Heat dissipating substrate and electronic device using the same |
WO2009131217A1 (en) | 2008-04-25 | 2009-10-29 | 京セラ株式会社 | Heat dissipating base body and electronic device using the same |
JP2019071328A (en) * | 2017-10-06 | 2019-05-09 | 株式会社豊田中央研究所 | Semiconductor packaging substrate, semiconductor module and method of manufacturing semiconductor packaging substrate |
JPWO2020203787A1 (en) * | 2019-03-29 | 2020-10-08 |
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